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Review for Chapter 7 . Multiply by Two-digit Numbers. 7.1: Multiply by powers of 10. Use mental math to help you multiply. 8 x 60 = 80 x 60 = 80 x 600 = 80x 6,000 =. 480 4,800 48,000 480,000. 7.1: Multiply by powers of 10. Use mental math to help you multiply. 5 x 60 =
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Review for Chapter 7 Multiply by Two-digit Numbers
7.1: Multiply by powers of 10 Use mental math to help you multiply. • 8 x 60 = • 80 x 60 = • 80 x 600 = • 80x 6,000 = 480 4,800 48,000 480,000
7.1: Multiply by powers of 10 Use mental math to help you multiply. 5 x 60 = 50 x 60 = 50 x 600 = 50x 6,000 = 300 3,000 30,000 300,000
7.2: Use rounding to estimate products Estimate the product by rounding each factor to its greatest place. 34 x23 30 ( I rounded 34 to 30) x20 ( I rounded 23 to 20) 600 is my estimate
7.2: Use rounding to estimate products Estimate the product by rounding each factor to its greatest place. 77 x 95 80 x 100 = 8,000 I rounded 77 to 80 and 95 to 100 and then used my mental math strategy to multiply.
7.2: Use rounding to estimate products Estimate the product by rounding each factor to its greatest place. 9,709 x 35 10,000 ( I rounded 9,709 to 10,000) X 40 ( I rounded 35 to 40) My best estimate is 400,000
7.3: Use base-ten blocks to model multiplication. Tell what multiplication sentence is shown by the array. Then find the product 11 x 6 = 66
7.3: Use base-ten blocks to model multiplication. Tell what multiplication sentence is shown by the array. Then find the product 19 x 16 = 304
7.4: Multiply two-digit numbers. Multiply. Show your work. 36 x17 36 x17 252 360 612
7.4: Multiply two-digit numbers. Multiply. Show your work. $ 25 x 38 $25 X 38 200 750 $950
7.5: Decide whether the answer to a problem is reasonable. Solve. Show your work. Use pictures, numbers, or words to show that your answer is reasonable. Mrs. Dondlinger eats 32 Powerberries each day. How many Powerberries would she eat in 14 days? 448 I took 32 and multiplied it by 14.
7.5: Decide whether the answer to a problem is reasonable. Solve. Show your work. Use pictures, numbers, or words to show that your answer is reasonable. Mrs. Meyers, Mr. Thiemann, Mrs. Anderson and Mrs. Dondlinger ran a relay race. Mrs. Meyers ran 125 meters, Mr Thiemann ran 93 meters, Mrs. Anderson ran 234 meters, and Mrs. Dondlinger 145 meters. How many meters did they run altogether? 125 + 93 + 234 + 145 = 597