a) 7 × 37 + 43 × 7 =
7 × (37 + 43) =
7 × 80 =
560
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b) 23 + 9 × 23 =
23 × (1 + 9) =
23 × 10 =
230
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c) 41 × 32 - 41 × 22 =
41 × (32 - 22) =
41 × 10 =
410
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d) 10 + 20 + 30 + 40 + 50 =
10 × (1 + 2 + 3 + 4 + 5) =
10 × 15 =
150
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e) 14 + 21 + 28 + 35 =
2 × 7 + 3 × 7 + 4 × 7 + 5 × 7 =
7 × (2 + 3 + 4 + 5) =
7 × 14 =
98
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f) 4×2017+2017×2013-2017 =
2017 × (4 + 2013 - 1) =
2017 × 2016 =
4 066 272
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