Number & Operations in Base Ten
1.NBT.C.5
1st Grade · Common Core Standards
Standard
Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.
Study materials
Study guide, practice problems, review, and practice test for this standard.
© Common Core State Standards Initiative. Used under CC BY 4.0. See thecorestandards.org for the official standards.