Five pages on adding three numbers, where the order you add in makes the work easy. Page 1 shows three dot cards: students circle the two that make 10, add them, then add the third (6 + 3 + 4: 6 + 4 = 10, 10 + 3 = 13). Page 2 does the same with numbers only, and the pair that makes 10 is not always side by side. Page 3 shows three dice with a double: add the double first (4 + 4 + 3: 8 + 3 = 11). Page 4 mixes the two: students decide whether the helpful pair makes a ten or a double, circle the pair, and add. Page 5 turns it around: find the missing number in 6 + __ + 4 = 15 by making the ten first. Each page starts with a worked example.
Before page 1, deal three cards from a deck (aces to nines) and ask, "Which two would you add first? Why?" Let students argue for a ten or a double. Show that adding in a different order gives the same sum by adding the same three numbers two ways on the board.
Roll three dice and add them. Ask your child which two to add first and why. Look for a double or two numbers that make 10, then add the last number on.
This pack supports the following Common Core State Standards for Mathematics:
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Adding three numbers with a sum up to 20 by looking for a ten or a double first. Students circle the pair that makes 10 or a double, add it first, then find missing numbers in sums like 6 + __ + 4 = 15.
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