Number Bonds to 20: Part-Part-Whole Past Ten

Every one of the six bonds on this page has 20 sitting in the whole circle. The diagram is unchanged — one whole joined to two parts, one of them dashed and empty — but the numbers are bigger: the child reads 20 and a part such as 13, and has to work out the partner that completes twenty. There are no counting dots and no counters printed anywhere, just the bond and the thinking that fills it.

Bonds of twenty are where the picture starts earning its keep as a strategy tool rather than a puzzle. Most children solve them by leaning on what they already know about ten: twenty is ten and ten, thirteen uses one ten and three more, so seven are left. Watching which route a child takes is genuinely informative — counting on by ones from thirteen says the ten structure has not landed yet, while an answer that arrives whole says it has. Either way, the pairs that make twenty are the facts sitting underneath two-digit addition a year or two later.

Print it free as a PDF and ask how each answer was found; the method matters more here than the six numbers do. Children who wobble can drop back to number bonds within 10 for a page, and those who fly through are ready for mental math within 20, where the same pairs reappear stripped of their circles.