Addition number family foundations

Students begin by learning that addition families have three values that are related through addition and subtraction. The numbers on the line are small numbers and the number at the end is the big number.

The process is:

• Say, ‘These are number families. All number families have three numbers. There are two small numbers and a big number. The two small numbers are on the arrow.’ Point to A, ‘The small numbers for this family are 3 and 2. The big number is 5. What’s the small number?’ and signal.
• Point to B and ask, ‘What are the small numbers in this family?’ and signal. ‘What’s the big number?’ and signal.
• Point to C and ask, ‘What are the small numbers in this family?’ and signal. ‘What’s the big number?’ and signal. Repeat until firm.
• Say, ‘You can say two addition facts for each family. One fact starts with the first small  number.’ Point to A, ‘What’s the first small number in this family?’ and signal. ‘Here’s the fact: 3 plus 2 equals 5. Here’s the fact that starts with the other small number: 2 plus 3 equals 5.’
• Say, ‘Everybody, say the fact that starts with the first small number’, and signal. ‘Say the fact that starts with the other small number’, and signal. Repeat until firm.
• Continue the same process with the other fact families, and then introduce the subtraction facts for the families.