Jack sews 3 shirts for each of his 3 kids. He sews 7 buttons in each shirt. How many buttons must Jack use for all the shirts? Think carefully first, then make a decision:
The total number of shirts for all his kids is 3 * 3 = 9 shirts. The total number of needed buttons is 9 * 7 = 63 buttons. So, the answer is 63.