# Lesson Worksheet: Relating Addition to Subtraction: Numbers up to 20 Mathematics • 1st Grade

In this worksheet, we will practice writing a family of addition and subtraction facts linking three numbers up to 20.

Q1:

We know that 8 plus 7 is 15. Here are the four number sentences for 8, 7, and 15.

Here are some number sentences for 5, 6, and 11. Which number sentence for 5, 6, and 11, is missing?

• A
• B
• C
• D
• E

Q2:

Which number sentence is wrong?

• A
• B
• C
• D
• E

Q3:

16 plus 3 is 19. Which number sentence is missing from the number sentences

• A
• B
• C
• D
• E

Q4:

Use to fill in the blanks in these number sentences.

Q5:

We know that . What other facts do we know? Find the missing numbers.  Q6:

The picture shows that: . Use the picture to complete the addition sentence: .

Q7:

We know that . Use the picture to check this if you need to. Use this addition fact to find the missing number in the subtraction sentence .

Q8:

This domino has 13 dots. How many dots are hidden? Q9:

We know that takeaway is .

Here are the four number sentences for 18, 7, and 11.

Now, think about the numbers 3, 4, and 7.

Which of the number sentences below does not belong?

• A
• B
• C
• D
• E