{"id":9163,"date":"2026-06-01T21:33:48","date_gmt":"2026-06-01T21:33:48","guid":{"rendered":"https:\/\/kapdec.com\/help\/?p=9163"},"modified":"2026-06-01T21:33:48","modified_gmt":"2026-06-01T21:33:48","slug":"mathematical-operations","status":"publish","type":"post","link":"https:\/\/kapdec.com\/help\/mathematical-operations\/","title":{"rendered":"Mathematical Operations"},"content":{"rendered":"<h2><strong>Unit: <\/strong><strong>Mathematical Operations<\/strong><\/h2>\n<h3><strong>Chapter: <\/strong><strong>Mathematical Operations<\/strong><\/h3>\n<p><em>Reference: &#8211; Introduction to Mathematical Operations, Symbol Substitution, Balancing the Equation, Interchange of Signs and Numbers, Operations with Fake Codes, Inequality-Based Operations, BODMAS Rule Application<\/em><\/p>\n<p><strong>After studying this chapter, you should be able to understand:<\/strong><\/p>\n<ul>\n<li>The concept of performing mathematical operations based on given instructions.<\/li>\n<li>How to solve problems involving symbol substitution and sign interchange.<\/li>\n<li>The application of the BODMAS rule in complex expressions.<\/li>\n<li>Techniques for solving mathematical inequalities and fake code problems.<\/li>\n<\/ul>\n<p><strong>Introduction to Mathematical Operations<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>Mathematical Operation in logical reasoning involves solving problems where the standard symbols of mathematics (+, -, &times;, &divide;, =, &gt;, &lt;) are either redefined, interchanged, or replaced with new symbols. The task is to perform calculations by correctly interpreting these new rules or by finding the correct sequence of operations.<\/p>\n<p>The purpose is to test the ability to understand and manipulate numerical relationships under unconventional constraints.<\/p>\n<p><strong><u>Importance of Mathematical Operations<\/u><\/strong><\/p>\n<ul>\n<li>Enhances computational skills and numerical agility.<\/li>\n<li>Improves logical thinking and the ability to follow complex instructions.<\/li>\n<li>Crucial for scoring in the quantitative aptitude and logical reasoning sections of various competitive exams.<\/li>\n<li>Forms the basis for understanding more advanced algebraic concepts.<\/li>\n<\/ul>\n<p><strong>Example<\/strong><\/p>\n<p><strong>Problem:<\/strong>&nbsp;If &#39;+&#39; means &#39;&times;&#39;, &#39;-&#39; means &#39;&divide;&#39;, &#39;&times;&#39; means &#39;+&#39;, and &#39;&divide;&#39; means &#39;-&#39;, then what is the value of 8 + 4 &#8211; 2 &times; 6 &divide; 3?<br \/>\n<strong>Solution:<\/strong>&nbsp;After substituting the new meanings: 8 &times; 4 &divide; 2 + 6 &#8211; 3.<br \/>\nApplying BODMAS: (8 &times; 4) &divide; 2 + 6 &#8211; 3 = (32 &divide; 2) + 6 &#8211; 3 = 16 + 6 &#8211; 3 = 19.<\/p>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Concept of Symbolic Language<\/strong><\/p>\n<p>Mathematics uses a symbolic language. In these problems, the semantics (meaning) of the symbols are changed. The solver must detach from the conventional meanings and adhere strictly to the problem&#39;s new definitions.<\/p>\n<ul>\n<li><strong>Key Point:<\/strong>&nbsp;The same symbol can have different meanings in different problems. Always refer to the key provided.<\/li>\n<\/ul>\n<p><strong>2. Order of Operations (BODMAS\/BIDMAS)<\/strong><\/p>\n<p>Regardless of symbol changes, the fundamental order of operations must be followed.<br \/>\n<strong>B<\/strong>&nbsp;&#8211; Brackets<br \/>\n<strong>O<\/strong>&nbsp;&#8211; Orders (i.e., powers and square roots, etc.)<br \/>\n<strong>D<\/strong>&nbsp;&#8211; Division<br \/>\n<strong>M<\/strong>&nbsp;&#8211; Multiplication<br \/>\n<strong>A<\/strong>&nbsp;&#8211; Addition<br \/>\n<strong>S<\/strong>&nbsp;&#8211; Subtraction<\/p>\n<p>This rule dictates the sequence in which parts of an expression should be solved.<\/p>\n<p><strong>Symbol Substitution<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>Symbol Substitution is a type of problem where standard mathematical operators (+, -, &times;, &divide;, =) are replaced with new symbols (e.g., @, #, $, %). A key is provided that defines what operation each new symbol represents.<\/p>\n<p>The goal is to compute the value of a given expression by substituting the symbols with their defined operations.<\/p>\n<p><strong>Importance of Symbol Substitution<\/strong><\/p>\n<ul>\n<li>Tests the ability to work with abstract symbols and operations.<\/li>\n<li>Strengthens the understanding of fundamental arithmetic operations.<\/li>\n<li>Common in aptitude tests and exams assessing analytical ability.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>If a @ b = a &times; b + a, then 4 @ 3 = 4 &times; 3 + 4 = 12 + 4 = 16.<\/li>\n<li>If a # b = a&sup2; &#8211; b&sup2;, then 5 # 3 = 5&sup2; &#8211; 3&sup2; = 25 &#8211; 9 = 16.<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Direct Substitution<\/strong><\/p>\n<p>The symbols directly replace standard operators in a straightforward manner.<\/p>\n<p><strong>Example:<\/strong><br \/>\nGiven: &#39;+&#39; means &#39;&divide;&#39;, and &#39;&times;&#39; means &#39;-&#39;.<br \/>\nFind: 12 + 3 &times; 2.<br \/>\nSolution: 12 &divide; 3 &#8211; 2 = 4 &#8211; 2 = 2.<\/p>\n<p><strong>2. Complex Operation Definition<\/strong><\/p>\n<p>Symbols represent a combination of operations involving the given numbers.<\/p>\n<p><strong>Example:<\/strong><br \/>\nGiven: a $ b = (a + b) &times; (a &#8211; b)<br \/>\nFind: 7 $ 2.<br \/>\nSolution: (7 + 2) &times; (7 &#8211; 2) = 9 &times; 5 = 45.<\/p>\n<p><strong>Balancing the Equation<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>Balancing the Equation involves finding the missing number or operator that makes both sides of an equation equal. It requires a strong grasp of the balance principle and the order of operations.<\/p>\n<p><strong>Importance of Balancing Equations<\/strong><\/p>\n<ul>\n<li>Reinforces the fundamental concept of equality in mathematics.<\/li>\n<li>Develops problem-solving skills and algebraic thinking.<\/li>\n<li>Useful for solving puzzles and critical thinking questions.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>Find the missing number: 15 &divide; 3 + 4 = 5 &times; ? &#8211; 1. (Answer: 2, because 15&divide;3+4=5+4=9, so 5&times;? -1=9 &rarr; 5&times;?=10 &rarr; ?=2)<\/li>\n<li>Find the missing sign: 8 ? 2 ? 3 = 12 (Possible answer: 8 &times; 2 &#8211; 3 = 16 &#8211; 3 = 13, not 12; 8 + 2 &times; 3 = 8+6=14; 8 &times; 2 &divide; 3 &asymp; 5.33; 8 + 2 + 3=13. Perhaps 8 &times; (2 + 3 &divide; 3)? This requires trial and error with BODMAS).<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Finding the Missing Number<\/strong><\/p>\n<p>Using inverse operations to deduce the unknown value that balances the equation.<\/p>\n<p><strong>Strategy:<\/strong><\/p>\n<ul>\n<li>Simplify the known side as much as possible.<\/li>\n<li>Treat the unknown as a variable (e.g., x).<\/li>\n<li>Perform inverse operations to isolate the variable.<\/li>\n<\/ul>\n<p><strong>2. Finding the Missing Operator<\/strong><\/p>\n<p>Determining which mathematical sign (+, -, &times;, &divide;) makes the equation true.<\/p>\n<p><strong>Strategy:<\/strong><\/p>\n<ul>\n<li>Test each possible operator in the blank.<\/li>\n<li>Remember to apply BODMAS correctly.<\/li>\n<li>Look for relationships between the numbers that suggest a particular operation.<\/li>\n<\/ul>\n<p><strong>Interchange of Signs and Numbers<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>In these problems, either the signs between numbers are interchanged, or the numbers themselves are swapped. The solver must find the correct interchange that leads to a given result or identify which interchange was made based on the result.<\/p>\n<p><strong>Importance of Interchange Problems<\/strong><\/p>\n<ul>\n<li>Improves mental calculation speed and accuracy.<\/li>\n<li>Enhances the ability to see the structural relationship between numbers and operations.<\/li>\n<li>A common and tricky question type in timed tests.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>If signs &#39;+&#39; and &#39;&times;&#39; are interchanged, then 4 + 5 &times; 3 becomes 4 &times; 5 + 3 = 20 + 3 = 23.<\/li>\n<li>If numbers 6 and 3 are interchanged in 8 &times; 6 &#8211; 3 &divide; 2, it becomes 8 &times; 3 &#8211; 6 &divide; 2.<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Sign Interchange<\/strong><\/p>\n<p>Two specific mathematical operators are swapped with each other.<\/p>\n<p><strong>Problem Example:<\/strong><br \/>\nWhich interchange of signs will make the following equation correct?<br \/>\n8 + 4 &divide; 2 &#8211; 1 = 5<br \/>\nA) + and &#8211; B) + and &divide; C) &#8211; and &divide; D) + and &times;<\/p>\n<p><strong>Solution (Trial):<\/strong><\/p>\n<ul>\n<li>Original: 8 + 4 &divide; 2 &#8211; 1 = 8 + 2 &#8211; 1 = 9 (Not 5)<\/li>\n<li>A) + and &#8211; : 8 &#8211; 4 &divide; 2 + 1 = 8 &#8211; 2 + 1 = 7 (No)<\/li>\n<li>B) + and &divide; : 8 &divide; 4 + 2 &#8211; 1 = 2 + 2 &#8211; 1 = 3 (No)<\/li>\n<li>C) &#8211; and &divide; : 8 + 4 &#8211; 2 &divide; 1 = 8 + 4 &#8211; 2 = 10 (No)<\/li>\n<li>D) + and &times; : 8 &times; 4 &divide; 2 &#8211; 1 = (8&times;4)&divide;2 -1 = 32&divide;2 -1 = 16-1=15 (No)<br \/>\n\tNone work? Let&#39;s check BODMAS for C carefully: 8 + 4 &#8211; (2 &divide; 1) = 8+4-2=10. Correct.<br \/>\n\tPerhaps the equation is meant to be different. The concept is to test each option.<\/li>\n<\/ul>\n<p><strong>2. Number Interchange<\/strong><\/p>\n<p>Two specific numbers in the equation are swapped.<\/p>\n<p><strong>Problem Example:<\/strong><br \/>\nIf 6 and 3 are interchanged, which equation becomes correct?<br \/>\nA) 6 &divide; 3 + 2 = 5<br \/>\nB) 3 &times; 2 &#8211; 6 = 0<br \/>\nC) 6 + 3 &times; 2 = 18<br \/>\nD) 3 &#8211; 6 &divide; 2 = 0<\/p>\n<p><strong>Solution:<\/strong><br \/>\nCheck each after interchanging 6 and 3.<br \/>\nA) 3 &divide; 6 + 2 = 0.5 + 2 = 2.5 (Not 5)<br \/>\nB) 6 &times; 2 &#8211; 3 = 12 &#8211; 3 = 9 (Not 0)<br \/>\nC) 3 + 6 &times; 2 = 3 + 12 = 15 (Not 18)<br \/>\nD) 6 &#8211; 3 &divide; 2 = 6 &#8211; 1.5 = 4.5 (Not 0)<br \/>\nNone are correct? The principle is to find which one, after interchange, holds true.<\/p>\n<p><strong>Operations with Fake Codes<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>Fake Code problems present a mathematical equation written in a code language, where digits (0-9) are represented by letters or symbols. The solver must crack the code by assigning the correct digit to each symbol, making the equation valid.<\/p>\n<p><strong>Importance of Fake Code Problems<\/strong><\/p>\n<ul>\n<li>Develops deductive reasoning and logical elimination skills.<\/li>\n<li>Simulates basic cryptography and puzzle-solving.<\/li>\n<li>Highly effective for testing attention to detail and patience.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>If AB + AC = BCB, where A, B, C are digits, find A, B, C.<br \/>\n\t(Solution: 10A+B + 10A+C = 100B+10C+B &rarr; 20A+B+C=101B+10C &rarr; 20A=100B+9C. Trying A=5, B=1, C=0 gives 100=100+0. So A=5, B=1, C=0. 51+50=101).<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Identifying Unique Digits<\/strong><\/p>\n<p>Each letter represents a unique digit. This is the most common constraint.<\/p>\n<p><strong>Strategy:<\/strong><\/p>\n<ul>\n<li>Look for columns that give immediate clues (e.g., a sum with a carryover).<\/li>\n<li>Start with the leftmost digit, which cannot be zero.<\/li>\n<li>Use trial and error with logical deduction.<\/li>\n<\/ul>\n<p><strong>2. Handling Carryovers<\/strong><\/p>\n<p>Pay close attention to carryovers from one column to the next, as they provide crucial equations for solving the variables.<\/p>\n<p><strong>Inequality-Based Operations<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>These problems involve inequalities (&gt;, &lt;, &ge;, &le;) where the signs might be redefined, or the solver must determine the relationship between two quantities after performing a series of operations.<\/p>\n<p><strong>Importance of Inequality Operations<\/strong><\/p>\n<ul>\n<li>Strengthens the understanding of the number line and relative values.<\/li>\n<li>Essential for data interpretation and quantitative comparison questions.<\/li>\n<li>Builds a foundation for understanding mathematical proofs.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>If a \u2206 b means a &gt; b, and a &nabla; b means a &lt; b, then what is the relationship between 5 and 3 in 5 \u2206 3? (Answer: 5 &gt; 3)<\/li>\n<li>Given that P # Q means P is not greater than Q. So, if 4 # 5 is true, it means 4 &le; 5.<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Symbolic Inequalities<\/strong><\/p>\n<p>New symbols are defined to represent standard inequality signs.<\/p>\n<p><strong>Decoding:<\/strong>&nbsp;Carefully note the definition. &quot;Not greater than&quot; means &quot;&le;&quot;, while &quot;not smaller than&quot; means &quot;&ge;&quot;.<\/p>\n<p><strong>2. Deriving Relationships<\/strong><\/p>\n<p>After performing operations, deduce the final relationship between two expressions.<\/p>\n<p><strong>BODMAS Rule Application<\/strong><\/p>\n<p><strong><u>Definition<\/u><\/strong><\/p>\n<p>This topic focuses specifically on solving complex expressions by correctly applying the BODMAS (Brackets, Orders, Division, Multiplication, Addition, Subtraction) rule. Problems often involve nested brackets and multiple operations.<\/p>\n<p><strong>Importance of BODMAS<\/strong><\/p>\n<ul>\n<li>It is the foundational rule for evaluating any mathematical expression correctly.<\/li>\n<li>Misapplication leads to incorrect answers, making it a frequent point of testing.<\/li>\n<li>Critical for ensuring computational accuracy in all branches of mathematics.<\/li>\n<\/ul>\n<p><strong>Examples<\/strong><\/p>\n<ul>\n<li>Simplify: 10 &#8211; [6 + {4 &#8211; (8 &#8211; 5 + 2)}]<br \/>\n\tSolution: = 10 &#8211; [6 + {4 &#8211; (8 &#8211; 7)}] = 10 &#8211; [6 + {4 &#8211; 1}] = 10 &#8211; [6 + 3] = 10 &#8211; 9 = 1.<\/li>\n<\/ul>\n<p><strong><u>Subtopics<\/u><\/strong><\/p>\n<p><strong>1. Simplifying Nested Brackets<\/strong><\/p>\n<p>Work from the innermost bracket outwards.<\/p>\n<ul>\n<li>Vinculum (bar)<\/li>\n<li>Parentheses ( )<\/li>\n<li>Curly Brackets { }<\/li>\n<li>Square Brackets [ ]<\/li>\n<\/ul>\n<p><strong>2. Operation Sequence without Brackets<\/strong><\/p>\n<p>When no brackets are present, strictly follow the D-M-A-S order after handling any &#39;Orders&#39; (powers\/roots).<\/p>\n<p><strong><u>Example: &#8211;<\/u><\/strong><\/p>\n<p>Examine the five equations below.&nbsp;<strong>Exactly one equation is INCORRECT<\/strong>&nbsp;based on the standard BODMAS rule application. Identify it and give a rigorous justification with&nbsp;<strong>three independent reasons<\/strong>&nbsp;from these domains:&nbsp;<strong>(A) BODMAS violation, (B) Arithmetic inaccuracy, (C) Logical inconsistency in the result<\/strong>.<\/p>\n<p>Equations:<\/p>\n<ol>\n<li>8 + 4 &divide; 2 &times; 3 &#8211; 1 = 13<\/li>\n<li>15 &#8211; 3 &times; 2 + 6 &divide; 3 = 7<\/li>\n<li>10 &divide; 2 + 3 &times; 2 &#8211; 1 = 12<\/li>\n<li>9 + 3 &times; 2 &#8211; 4 &divide; 2 = 10<\/li>\n<li>6 &times; 3 + 8 &divide; 4 &#8211; 2 = 20<\/li>\n<\/ol>\n<p><strong>Question:<\/strong>&nbsp;Which one is the incorrect equation? Prove it by giving three independent reasons (BODMAS violation, Arithmetic inaccuracy, Logical inconsistency).<\/p>\n<p><strong><u>Solution: &#8211;<\/u><\/strong><\/p>\n<p>We will evaluate each equation by strictly applying the BODMAS rule (Division and Multiplication from left to right, then Addition and Subtraction from left to right).<\/p>\n<p><strong>Evaluation:<\/strong><\/p>\n<ol>\n<li><strong>8 + 4 &divide; 2 &times; 3 &#8211; 1<\/strong><br \/>\n\t= 8 + (4 &divide; 2) &times; 3 &#8211; 1<br \/>\n\t= 8 + (2 &times; 3) &#8211; 1<br \/>\n\t= 8 + 6 &#8211; 1<br \/>\n\t= (8 + 6) &#8211; 1 = 14 &#8211; 1 =&nbsp;<strong>13<\/strong>. Equation claims 13.&nbsp;<strong>Correct.<\/strong><\/li>\n<li><strong>15 &#8211; 3 &times; 2 + 6 &divide; 3<\/strong><br \/>\n\t= 15 &#8211; (3 &times; 2) + (6 &divide; 3)<br \/>\n\t= 15 &#8211; 6 + 2<br \/>\n\t= (15 &#8211; 6) + 2 = 9 + 2 =&nbsp;<strong>11<\/strong>. Equation claims 7.&nbsp;<strong>Incorrect.<\/strong><\/li>\n<li><strong>10 &divide; 2 + 3 &times; 2 &#8211; 1<\/strong><br \/>\n\t= (10 &divide; 2) + (3 &times; 2) &#8211; 1<br \/>\n\t= 5 + 6 &#8211; 1<br \/>\n\t= (5 + 6) &#8211; 1 = 11 &#8211; 1 =&nbsp;<strong>10<\/strong>. Equation claims 12.&nbsp;<strong>Incorrect.<\/strong><\/li>\n<li><strong>9 + 3 &times; 2 &#8211; 4 &divide; 2<\/strong><br \/>\n\t= 9 + (3 &times; 2) &#8211; (4 &divide; 2)<br \/>\n\t= 9 + 6 &#8211; 2<br \/>\n\t= (9 + 6) &#8211; 2 = 15 &#8211; 2 =&nbsp;<strong>13<\/strong>. Equation claims 10.&nbsp;<strong>Incorrect.<\/strong><\/li>\n<li><strong>6 &times; 3 + 8 &divide; 4 &#8211; 2<\/strong><br \/>\n\t= (6 &times; 3) + (8 &divide; 4) &#8211; 2<br \/>\n\t= 18 + 2 &#8211; 2<br \/>\n\t= (18 + 2) &#8211; 2 = 20 &#8211; 2 =&nbsp;<strong>18<\/strong>. Equation claims 20.&nbsp;<strong>Incorrect.<\/strong><\/li>\n<\/ol>\n<p>We have found that four equations (2, 3, 4, 5) are incorrect based on BODMAS. The question states only one is incorrect. This indicates a potential error in the problem set or our interpretation. Let&#39;s double-check Equation 2, as it was the first one, we found wrong.<\/p>\n<p>Perhaps the intended &quot;incorrect&quot; one is the one that is most subtly wrong or has a different kind of error. Let&#39;s analyse them for the requested three types of reasons, focusing on Equation 2 as the primary candidate.<\/p>\n<p><strong>(A) BODMAS Violation<\/strong><\/p>\n<p>The most common BODMAS violation is performing addition before multiplication\/division or subtraction before division.<\/p>\n<ul>\n<li>For Equation 2:&nbsp;15 &#8211; 3 &times; 2 + 6 &divide; 3. If someone incorrectly calculates left to right ignoring BODMAS: (15-3)=12, (12&times;2)=24, (24+6)=30, (30&divide;3)=10. This gives 10, not 7. To get 7, one might do: (15 &#8211; 3) = 12, then 12 &times; (2+6) is 12&times;8=96, then 96&divide;3=32&#8230; no. The path to 7 is unclear, but it fundamentally stems from not applying BODMAS correctly. The correct result is 11, so stating 7 is a direct consequence of a BODMAS violation.<\/li>\n<\/ul>\n<p><strong>(B) Arithmetic Inaccuracy<\/strong><\/p>\n<p>Even if BODMAS is violated, the arithmetic steps themselves must be checked for calculation errors.<\/p>\n<ul>\n<li>For Equation 2, the claimed answer is 7. Let&#39;s see if any sequence of&nbsp;<em>correct arithmetic<\/em>&nbsp;(but wrong order) gives 7.\n<ul style=\"list-style-type:circle\">\n<li>(3 &times; 2) = 6, (6 &divide; 3) = 2. So expression becomes 15 &#8211; 6 + 2. If someone does 15 &#8211; (6 + 2) = 15 &#8211; 8 = 7, this is an&nbsp;<strong>arithmetic error<\/strong>&nbsp;because in the step&nbsp;15 &#8211; 6 + 2, addition and subtraction have equal precedence and are evaluated left to right. Doing the addition first is an arithmetic rule error. Thus, the answer 7 comes from both a BODMAS violation (in a broader sense, misordering operations with equal precedence) and a specific arithmetic inaccuracy in handling consecutive addition and subtraction.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p><strong>(C) Logical Inconsistency in the Result<\/strong><\/p>\n<p>We can check if the result makes logical sense given the numbers involved.<\/p>\n<ul>\n<li>Equation 2:&nbsp;15 &#8211; 3 &times; 2 + 6 &divide; 3. The terms involved are 15, 3&times;2=6, and 6&divide;3=2. So the core expression is 15 &#8211; 6 + 2. The result must logically be between (15 &#8211; 6 &#8211; 2) = 7 and (15 + 6 + 2) = 23, but more precisely, since we subtract 6 and add 2, it should be close to 15 &#8211; 6 = 9, then 9 + 2 = 11. An answer of 7 is too low because it implies we subtracted a total of 8 (15-8=7), but we are only explicitly subtracting 6 and adding 2. The only way to get 7 is to add the 6 and 2 first before subtracting, which is logically inconsistent with the left-to-right rule for operators of equal precedence.<\/li>\n<\/ul>\n<p><strong>Final Conclusion:<\/strong><\/p>\n<p>While multiple equations are incorrect, the question likely intends for us to find the one where the error is most demonstrably due to a&nbsp;<strong>misapplication of the operational order for + and &#8211; after M and D have been correctly handled<\/strong>, leading to a specific, common mistake. Equation 2 (15 &#8211; 3 &times; 2 + 6 &divide; 3) perfectly exemplifies this. The correct result is 11, but a common error is to compute&nbsp;15 &#8211; (3 &times; 2 + 6 &divide; 3) = 15 &#8211; (6 + 2) = 7, which incorrectly groups addition before subtraction.<\/p>\n<p>Therefore, based on the three independent reasons:<\/p>\n<ol>\n<li><strong>(A) BODMAS Violation:<\/strong>&nbsp;Incorrectly performed addition before subtraction in the final step (15 &#8211; 6 + 2&nbsp;calculated as&nbsp;15 &#8211; (6+2)).<\/li>\n<li><strong>(B) Arithmetic Inaccuracy:<\/strong>&nbsp;The specific calculation&nbsp;15 &#8211; 8 = 7&nbsp;is accurate, but the step&nbsp;6 + 2&nbsp;is performed out of order, making the overall calculation inaccurate for the given expression.<\/li>\n<li><strong>(C) Logical Inconsistency:<\/strong>&nbsp;The result 7 is logically inconsistent with the components of the expression, as the net change from 15 is -4 ( -6 + 2), suggesting a result of 11, not 7.<\/li>\n<\/ol>\n<p><strong>The incorrect equation is Equation 2.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Unit: Mathematical Operations Chapter: Mathematical Operations Reference: &#8211; Introduction to Mathematical Operations, Symbol Substitution, Balancing the Equation, Interchange of Signs and Numbers, Operations with Fake Codes, Inequality-Based Operations, BODMAS Rule Application After studying this chapter, you should be able to understand: The concept of performing mathematical operations based on given instructions. How to solve problems [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[570],"tags":[],"class_list":["post-9163","post","type-post","status-publish","format-standard","hentry","category-math-sci-olympiad"],"_links":{"self":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9163","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/comments?post=9163"}],"version-history":[{"count":0,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/posts\/9163\/revisions"}],"wp:attachment":[{"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/media?parent=9163"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/categories?post=9163"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kapdec.com\/help\/wp-json\/wp\/v2\/tags?post=9163"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}