Mathematics · Grades K–2
Number skills · Formula sheet
Rules, conditions and small examples in one printable reference.
Remember this
Make ten
Start with the known part and count on to ten.
part + missing part = 10
10 − 9 = 1
Tens and ones
A group of ten can be exchanged for ten ones.
number = 10 × tens + ones
8 × 10 + 1 = 81
Round to the nearest ten
For positive whole numbers, inspect the ones digit.
0–4 → down; 5–9 → up
241 → 240
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.