Help students practice addition and subtraction skills. Activities include adding facts to 20, subtracting using a number line, adding and subtracting sets, adding and subtracting 2-digit numbers, regrouping and more. Durable pages allow for easy erasing, offering endless opportunities for learning fluency. Use a dry-erase marker, sold separately, to fill in the answers. When finished, simply wipe away and start again. 32 pages, measures 7x9". For grade 1.