If 7 − 4 = 3, what is 7,000 − 4,000? This 3rd grade subtraction patterns worksheet builds big subtractions from small basic facts. A worked example starts with 9 − 5 = 4 and grows it to 90,000 − 50,000. Then four patterns of six lines each ask your child to fill the blanks. Sometimes the missing number is the answer, sometimes the first or second number. A second page gives the answer key.