Standard Alignments:

TEKS Math: 1.5.C

(C) Use relationships to determine the number that is 10 more and 10 less than a given number up to 120

CCSS Math: 1.NBT.5

1.NBT.5 Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.