Step 1 / 5

Find the missing number

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Count in order: 1, 2, 3 … 20.

Addition Village · Learn first

Example

What number goes in the box?

8, ▢, 10, 11, 12

Answer: 9

Steps in this unit · Number order

1 2 3 4 5

← Many ways to show a number What comes next? →

Number order · Numbers & Operations

Put 1 to 20 in order, find missing and next numbers, and place numbers on a number line.

Count in order: 1, 2, 3 … 20.

This is step 1 of unit 5, “Number order”, in Stage 1: Numbers to 20, adding and subtracting (ages 6–7). A round has 8 problems; 90% or better earns three stars. Everything is free with no sign-up, and your stars and XP are saved on this device.