2.OA.C.3 Grade 2 · Operations and Algebraic ThinkingDetermine whether a group of objects (up to 20) has an odd or even number of members, e.g., by pairing objects or counting them by 2s; write an equation to express an even number as a sum of two equal addends.Common Core State Standards for Mathematics, as adopted in the Massachusetts Curriculum Framework for Mathematics (2017), Grade 2.
Play the game: DoublesSteps 10, 30 of the ColorMyMath curriculum · free, no sign-up →Addition is a length — dots laid end to end on the number line. Taking away comes down the same line. Every fact is shown as a picture before it is ever asked for from memory.
Every page is free and open — nothing to install, no account, and it works on a phone or a classroom board. Every number has its own color: 1 red, 2 orange, 3 yellow, 4 green, 5 blue, 6 purple, 7 brown, 8 pink, 9 cyan, and a number is that many colored dots.
Step 10Doubling 1-5 to make 2, 4, 6, 8, 10Step 12Adding 2: counting by 2s to 10Step 19Subtracting 2: counting down by 2s from 10Step 20Adding 2: counting by 2s to 20Step 22Subtracting 2: counting down by 2s from 20Step 30Doubling 6-10 to make 12, 14, 16, 18, 202.OA.A.1One- and two-step word problems within 1002.OA.B.2Add and subtract within 20 fluently; by the end of grade 2 know every sum of two one-digit numbers and the matching subtraction facts2.OA.C.4Count the objects in a rectangular array up to 5 by 5 by addingColorMyMath · getridoftheteacher.com · every number has its own color, and a number is that many colored dots. Matching a game to a standard is a judgement call; the official text is at doe.mass.edu.