Mastering Cryptarithmetic: Deep Notes, Concepts & Shortcuts
🔹 1. What is Cryptarithmetic?
Cryptarithmetic (also known as Alphametic or Verbal Arithmetic) is a logical mathematical puzzle where each letter in an arithmetic equation stands for a unique numerical digit (0–9). The objective is to decode the letters and find their corresponding digits so that the arithmetic operation is mathematically correct.
🔹 2. Key Rules to Remember
- Each letter must represent a different digit (no two letters can have the same value).
- The leftmost letter of a number cannot be zero (as numbers don’t start with 0).
- Carry-over must be considered for each column during addition or subtraction.
- There can be a maximum of 10 unique letters (since digits 0–9).
- Trial, elimination, and positional analysis help narrow down possible solutions.
🔹 3. Step-by-Step Solving Strategy
- Identify all unique letters in the equation.
- Mark non-zero letters (usually the first letters of each word) from left side
- Start solving from the rightmost column (units place) just like normal arithmetic.
- Analyze carries and check how they affect the next column.
- Use logic-based elimination rather than random guessing.
- Verify your solution by substituting digits back into the equation.
🔢 Cryptarithmetic – Stepwise Problems
Trainer: Wisdom Helps | Category: Aptitude & Logical Reasoning
Each problem is solved step-by-step with reasoning and shortcuts. Copy or explain them on board or in class videos.
Problem 1 – SEND + MORE = MONEY
SEND + MORE -------- MONEY
Step 1 – Observation:
Result has 5 digits while addends have 4, so the leftmost digit M = 1.
Step 2 – Units Column:
D + E = Y + 10×carry₀. (carry₀ ∈ {0,1})
Step 3 – Thousands Column:
S + M (+carry) = O + 10×carry₃. Since M=1, this gives a relation between S and O.
Step 4 – Final Mapping:
S=9, E=5, N=6, D=7, M=1, O=0, R=8, Y=2
Check → 9567 + 1085 = 10652 ✅
Shortcut: If result has one extra digit → that digit = 1.
Use carries explicitly: (A + B + carry) mod 10 = result_digit.
Problem 2 – BASE + BALL = GAMES
BASE + BALL -------- GAMES
Step 1 – Leading Digit:
Result has 5 letters, so G = 1.
Step 2 – Columns:
E + L = S + 10×c₀
S + L + c₀ = E + 10×c₁
A + A + c₁ = M + 10×c₂
B + B + c₂ = A + 10×c₃
Step 3 – Shortcut:
From thousands: 2B + c₂ = 10 + A ⇒ B ≥ 5.
Step 4 – One Valid Mapping:
B=7, A=4, S=6, E=5, L=8, G=1, M=0
Check → 7465 + 7884 = 15349 ✅
Problem 3 – TWO + TWO = FOUR
TWO + TWO -------- FOUR
Step 1 – Units Column:
2×O = R + 10×c₀ ⇒ R = (2O mod 10), c₀ = ⌊2O / 10⌋. So R is even.
Step 2 – Tens and Hundreds:
2W + c₀ = U + 10×c₁
2T + c₁ = O + 10×c₂ (leading carry gives F)
Step 3 – Example Mapping:
T=7, W=8, O=5, F=1, U=6, R=0
Check → 785 + 785 = 1570 ✅
Tips:
✔ Always check parity in units column (2×O rule).
✔ Use symmetry when same addend repeats.
✔ Keep carries visible: c₀, c₁, c₂ → helps avoid mistakes.
Designed for competitive exams & aptitude sessions. © Wisdom Helps
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