Part-whole diagrams to 5, 10 and 20 — one value left blank to fill in, each set with a matching answer key. Number bonds are the K–2 foundation of addition and subtraction. Always free, no signup.
Open the number-bonds builder →A number bond is a picture of part-part-whole: a 'whole' number on top joined to its two 'parts' below. It shows at a glance that the parts combine to make the whole — the foundation of addition and subtraction.
Number bonds build the flexible number sense kids need to add and subtract fluently. Knowing the pairs that make 10 especially — the make-ten facts — speeds up almost all later mental math and place-value work.
Most kids start with bonds to 5, then the all-important bonds to 10, then bonds to 20. Each worksheet above leaves one value blank — a part or the whole — so children practise in both directions.
Yes — every set is free to generate and print, with answer keys, no account and no watermark.