Symbol-substitution questions where +, −, ×, ÷ are swapped or coded — solved by first decoding the true operation behind each symbol.
📖 ~11 min read🧩 SSC Reasoning
Introduction
Mathematical Operations questions replace standard arithmetic symbols (+, −, ×, ÷) with different symbols
or swap two operations with each other — you must first decode the actual operation each symbol
represents, then re-solve the expression using standard BODMAS.
Diagram — Symbol Substitution Mapping
Symbols shown in the question don't perform their usual job — substitute the real operation first, then calculate.
Two Question Formats
Format
What to Do
Direct substitution ("+" means "×", etc.)
Replace every symbol with its stated real meaning, then solve using BODMAS
Find the correct equation from options
Test each option by substituting the given symbol meanings and checking which one balances
Q. If '+' means '÷', '−' means '×', '×' means '+', and '÷' means '−', find the value of: 8 × 4 + 2 − 3
Q. If 'A' means '+', 'B' means '−', 'C' means '×', and 'D' means '÷', which of these is correct: 10 C 2 A 5 D 5 = 21?
Substitute: 10 × 2 + 5 ÷ 5
BODMAS: 5÷5=1, 10×2=20, 20+1 = 21 ✓ — the equation is correct
Number-Substitution Pattern
Q. If 5 is coded as 3, 8 is coded as 6, and the operation follows "subtract 2 from every number," what is the coded value of 5 + 8 = 13?
Coded 5 = 3, Coded 8 = 6, Coded 13 = 11
Check: 3 + 6 = 9 ≠ 11 — the coding rule modifies operands but not necessarily the arithmetic relationship, so state the answer based strictly on the coded value asked: 11 (coded value of 13)
💡 Exam Tip: Write the substituted expression completely (swap every symbol first) before doing any arithmetic — attempting to calculate and substitute simultaneously is the most common source of careless errors in this chapter.
✅ Practice Focus: Full symbol substitution before calculating · Re-applying BODMAS after substitution · "Find the correct equation" testing method · Distinguishing symbol-coding from number-coding questions.