What is a number bond?

A picture of a number split into two parts: the whole at the top and two parts below. 10 can be 7 and 3, or 6 and 4.

What is a fact family?

Three numbers that make four facts: 7 + 3 = 10, 3 + 7 = 10, 10 – 7 = 3 and 10 – 3 = 7.

Do children learn number bonds before Primary 1?

Often, yes. The NEL Framework for K1 and K2 includes naming the parts of a whole up to 10, usually with objects and games rather than worksheets. Primary 1 builds on this and uses bonds for addition and subtraction within 20.

Number Bonds and Fact Families Worksheets: to 5, 10 and 20

Why number bonds matter

Knowing that 8 and 2 make 10 is the key to adding 8 + 5 in your head: 8 + 2 + 3. Bonds and fact families make that connection visible.

In the MOE curriculum

K1–K2The NEL Framework asks children to name the parts that make a whole up to 10, such as 5 as 2 and 3.
Primary 1Addition and subtraction concepts, how the two are related, and mental calculation within 20.
Big ideaThe 2021 syllabus names part-whole relationships as one way of seeing equivalence.

Number bonds are the usual Singapore picture of part-whole thinking: a circle for the whole joined to circles for its two parts. Children build them with cubes or counters first, then draw them, then write them as number sentences, following the concrete–pictorial–abstract approach.

Bonds to 10 also help with subtraction within 20: 13 – 8 can be found by taking 8 from 10 and adding the 3 left over. Later, a number bond stretched into a bar becomes the part-whole model in model drawing.

Summarised in our own words from the MOE Primary Mathematics Syllabus (2021, updated October 2025) and the Nurturing Early Learners Framework (2022).