 # 100 Solve 3 X 7 = ? using base 10 blocks Build a 3 X 7 array! X.

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100

Solve 3 X 7 = ? using base 10 blocks Build a 3 X 7 array! X

Solve 3 X 7 = using base 10 blocks Build a 3 X 7 array! How many blocks are in your array? So 3 x 7 = 21. 21 X

X Solve 60 X 50 = using base 10 blocks Build a 60 X 50 array! Try to use as FEW blocks as possible. (Trade sets of 10 longs for 1 flat.)

How many blocks are in your array? So 60 x 50 = 3,000. 3,000 X 100

X Solve 67 X 53 = using base 10 blocks Build a 67 X 53 array! Try to use as FEW blocks as possible. (Trade sets of 10 longs for 1 flat. Trade sets of 10 cubes for 1 long.)

X 100

How many blocks are in your array? So 67 X 53 = 3,551. 3,551 30 = 3,000 35 = 350 18 = 180 21 = 21 3,551

We call this method the Partial Products Algorithm. It looks like this…

Calculate 50 X 60 67 X 53 Calculate 50 X 7 3,000 350 180 21 Calculate 3 X 60 Calculate 3 X 7 + Add the results 3,551 To find 67 x 53, think of 67 as 60 + 7 and 53 as 50 + 3. Then, multiply each part of one sum by each part of the other. Now, add the results

Calculate 10 X 20 14 X 23 Calculate 20 X 4 200 80 30 12 Calculate 3 X 10 Calculate 3 X 4 + Add the results 322 #1 Build this with your blocks.

Calculate 30 X 70 38 X 79 Calculate 70 X 8 2, 100 560 270 72 Calculate 9 X 30 Calculate 9 X 8 + Add the results #2 Build this with your blocks. 3002

 Now, try some in your Math Journal.  You may still use the blocks or drawings of blocks.

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