Numbers to 20
Numbers to 20 is the skill of counting, reading, writing and ordering whole numbers from 0 to 20, and finding one more or one less than a given number. It is taught in Year 1 as part of the National Curriculum and forms the foundation for place value, addition and subtraction later in KS1.
Before you start
No specific prerequisites - this is a good place to start.
Method
- Count objects one at a time, saying each number name in order, to find how many there are.
- Learn the order of numbers to 20 forwards and backwards, so you can find the number just before or just after any number.
- Compare two numbers by picturing them on a number line: the number further to the right is bigger.
- Use 'one more' (add 1) and 'one less' (subtract 1) to move quickly along the number line.
- Split numbers between 10 and 20 into '1 ten and some ones' (e.g. 16 = 1 ten and 6 ones) to see the place value.
- When putting a list of numbers in order, find the smallest first, then find the next smallest, and so on.
Worked example
Put these numbers in order, starting with the smallest: 16, 4, 11
- Look at each number and think about where it sits on a number line from 0 to 20.
- 4 is the smallest of the three numbers, so it goes first.
- Compare 16 and 11: 11 comes before 16 on the number line, so 11 is smaller than 16.
- Write the numbers in order from smallest to largest: 4, 11, 16.
Practice questions
Try each question, then tap to reveal the answer.
Exam-style questions
Written in the style of a KS1 Maths exam paper, with a full mark scheme.
There are 20 buttons in a tin. Mia takes out 7 buttons, then puts back 3 buttons. How many buttons are in the tin now?
Write these numbers in order, starting with the smallest: 18, 6, 13
Ade has 6 toy cars. He buys 9 more toy cars, then gives 4 toy cars to his cousin. How many toy cars does Ade have now?
Free printable worksheet
Want more practice on paper? Download the numbers to 20 worksheet pack - 7 pages of exam-style questions with a full mark scheme. No sign-up, no email wall - just the PDF, free for personal and classroom use.
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