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Shortcuts in Addition. By Monica Yuskaitis. Adding Long Columns. Since addition is Commutative it doesn’t matter which numbers you add first. 4 + 2 + 5 + 1 = 12 1 + 4 + 5 + 2 = 12. Adding Long Columns. Begin by looking for combinations of ten. 34 57 83 26. +. Adding Long Columns.
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Shortcuts in Addition By Monica Yuskaitis
Adding Long Columns • Since addition is Commutative it doesn’t matter which numbers you add first. 4 + 2 + 5 + 1 = 12 1 + 4 + 5 + 2 = 12
Adding Long Columns • Begin by looking for combinations of ten. 34 57 83 26 +
Adding Long Columns • Add up your ten combinations first. 2 34 57 83 26 + 0
Adding Long Columns • Add up your ten combinations again. 34 57 83 26 2 + 2 0 0
Review Combinations of Ten 9 5 • 1 + = 10 5 + = 10 • 8 + = 10 7 + = 10 • 2 + = 10 6 + = 10 • 4 + = 10 3 + = 10 • 9 + =10 2 3 8 4 6 7 1
Adding Long Columns • When a number keeps repeating use multiplication. 2 32 36 88 26 36 + 8
Adding Long Columns • When a number keeps repeating use multiplication. 2 32 36 88 26 36 + 2 1 8
