Looking for the BEST addition and subtraction within 20 1st grade worksheets? These adding and subtracting up to 20 activities cover using pictures and objects to add and subtract, adding and subtracting on a number line, counting on to add, counting back to subtract, making 10 to add and subtract, using doubles to add and subtract, fact families, related addition and subtraction problems, number bonds, true and false, and SO MUCH MORE! This 6 week adding and subtracting up to 20 unit is filled