Give a six-year-old three numbers to add, and the usual plan is to go left to right, one long count. Yet 8 + 8 + 3 gets much easier once you spot the 8 + 8. This 1st grade add three numbers worksheet teaches that shortcut. In the top part, ten sums each start with a double, and the worked example shows the move: 11 + 11 + 8 becomes 22 + 8, then 30. Some totals go past 20, up to the thirties, so the doubles really earn their keep. In the bottom part, five boxes ask for the missing number to make ten, as in 3 + … = 10. A second page gives the answer key.