What a number bond looks like
A number bond is usually drawn as a 'whole' circle joined to two 'part' circles. If the whole is 10 and one part is 6, the other part is 4. The same picture shows four facts at once: 6 + 4 = 10, 4 + 6 = 10, 10 , 6 = 4 and 10 , 4 = 6.
Why number bonds matter
Number bonds make the part,whole relationship concrete, so children stop counting on their fingers and start recalling facts. Bonds to 10 in particular unlock mental strategies like 'make ten' for harder sums (8 + 5 becomes 8 + 2 + 3).
How to teach them
- Start with objects: split a group of counters into two piles and name the parts.
- Draw the bond and fill in the missing part.
- Drill bonds to 10, then to 20.
- Show how each bond gives two addition and two subtraction facts.