LADYBUG Skill - Abacus Training

Ladybug, the second abacus skill, introduces the concept of complement addition. Students learn the 5 complement pairs, e.g. 9-1, 8-2, 7-3, 6-4, 5-5, in our base10 system and how to use complements in addition. This is refered to as 10 pair complement addition.

Example

9
6
4
-7