Arithmetic, DIV and MOD

Arithmetic operators

• Pseudocode uses + - * / for the usual maths.
• / gives a real answer (with a decimal point).

OUTPUT 6 + 2      // → 8
OUTPUT 6 * 2      // → 12
OUTPUT 7 / 2      // → 3.5

DIV: whole-number division

• DIV divides and throws the remainder away.
• 17 DIV 5 is 3 — 5 goes into 17 three whole times.

OUTPUT 17 DIV 5   // → 3

MOD: the remainder

• MOD gives the remainder after dividing.
• 17 MOD 5 is 2. A number is even when N MOD 2 = 0.

OUTPUT 17 MOD 5   // → 2

Watch out

• DIV and MOD work on whole numbers; plain / gives a decimal.
• Together they "undo" a division: (17 DIV 5) * 5 + (17 MOD 5) = 17.

Common mistakes

• DIV is whole-number division; MOD is the remainder.
• Use brackets to control the order of arithmetic.

Now you try

• Use + - * /, and DIV / MOD.
• Press Check answer to test it.