IXL | Subtract doubles | 1st grade math

or

Subtract.

4

–

2

=

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Learn with an example

question

Subtract.

2

–

1

=

key idea

To subtract, it can be helpful to think of a related addition fact. (Related facts use the same numbers.)

Related facts
Doubles addition	Doubles subtraction
1 + 1 = 2	2 – 1 = 1
2 + 2 = 4	4 – 2 = 2
3 + 3 = 6	6 – 3 = 3
4 + 4 = 8	8 – 4 = 4
5 + 5 = 10	10 – 5 = 5
6 + 6 = 12	12 – 6 = 6
7 + 7 = 14	14 – 7 = 7
8 + 8 = 16	16 – 8 = 8
9 + 9 = 18	18 – 9 = 9
10 + 10 = 20	20 – 10 = 10

solution

Look at the subtraction sentence.

2

–

1

=

Think of the related addition sentence. It uses the same numbers.

1

+

=

2

The doubles addition fact for 1s shows the missing number. It is 1.

1

+

1

=

2

So:

2

–

1

=

1

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Work it out

Not feeling ready yet? These can help:

K.1Subtraction facts - up to 10