What is a number bond?

A number bond is a simple model showing how a whole number is made of two (or more) parts. It's drawn as a 'whole' joined to its 'parts', and it makes the link between addition and subtraction visible , the same bond gives two addition facts and two subtraction facts.

Examples

• 7 is 3 and 4 (3 + 4 = 7).
• 10 is 6 and 4, so 10 − 6 = 4.
• A bond for 8: 5 and 3.

Quick facts

• Number bonds to 10 are the foundation of mental math strategies like 'make ten'.
• One bond gives four facts: 3+4=7, 4+3=7, 7−3=4, 7−4=3.