Arithmetic, relational and Boolean operators

Overview

Real division, DIV and MOD with worked examples, the order of operations, the six relational operators, and AND, OR and NOT in conditions such as a mark between 1 and 10.

What you need to know

Answer each one before you reveal it.

Questions from this subtopic

Each one with the model answer underneath.

1. 1

   What does the / operator do?

   Model answer

   The / operator carries out real division, so the result can have a fractional part. The expression 11 / 4 gives 2.75.

2. 2

   What does x ← 17 DIV 5 store in x?

   Model answer

   The variable x stores 3. The DIV operator gives the whole-number part of the division and discards the remainder.

3. 3

   What does x ← 17 MOD 5 store in x?

   Model answer

   The variable x stores 2. The MOD operator gives the remainder, since 3 × 5 + 2 = 17.

4. 4

   A program packs 50 eggs into boxes of 6. What do 50 DIV 6 and 50 MOD 6 give?

   Model answer

   The expression 50 DIV 6 gives 8 full boxes, and 50 MOD 6 gives 2 eggs left over. The check 8 × 6 + 2 = 50 confirms this.

5. 5

   How can MOD test whether a number is even?

   Model answer

   A number n is even if n MOD 2 = 0. An odd number leaves a remainder of 1 when divided by 2.

6. 6

   What does 3 + 4 * 2 give?

   Model answer

   The expression gives 11. Multiplication is carried out before addition, so 4 * 2 is worked out first.

Other ways to work this

The same content, four other ways.

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Six ways to work the same material.