Coding–Decoding • Topic 4 of 4

Symbol & Conditional Coding

Here a table assigns conditions: e.g., 'if a number is even, code it ↑; if odd, code it ↓', or symbols stand for operations. Apply each condition in the stated order, watching for an exception clause at the end.

Apply the rules in order — and read the exception

Conditional coding gives a small rulebook (often with a final "but if…" exception). Apply the rules left to right and check every digit/letter against them. A common type makes a symbol stand for an operation: "if + means ×", then evaluate with that meaning under BODMAS.

The last line matters most. SSC almost always adds an exception ("…but if the first element is a vowel, swap the codes"). Read all conditions before you start coding, or you will miss it.

✅ Solved examples

1. Code even digits as E, odd as O. Code 4 7 2.
4=E, 7=O, 2=E → E O E.
2. If + means ×, code 3 + 4.
+ acts as ×: 3 × 4 = 12.
3. Code vowels as 1, consonants as 0. Code CAT.
C=0, A=1, T=0 → 0 1 0.
4. If ÷ means +, evaluate 10 ÷ 5.
÷ acts as +: 10 + 5 = 15.

✏️ Practice — try these, take hints as needed

1. Even=E, odd=O. Code 9 6 3.
Check parity.
—
—
O E O
2. If × means −, evaluate 8 × 3.
× acts as −.
—
—
5
3. Vowel=1, consonant=0. Code DOG.
D=0,O=1,G=0.
—
—
0 1 0
4. If − means ×, evaluate 6 − 2.
− acts as ×.
—
—
12
5. Even=E, odd=O. Code 5 8 1.
—
—
—
O E O

📝 Topic test — 8 questions

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