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怎么进行简便计算12.5×(7.8×1.6+0.2×1.6)7.4×5.6+7.4×5.4-74×0.19.9×9.9+1.99

题目详情
怎么进行简便计算
12.5 ×(7.8×1.6+0.2×1.6)
7.4×5.6+7.4×5.4-74×0.1
9.9×9.9+1.99
▼优质解答
答案和解析
12.5 ×(7.8×1.6+0.2×1.6)
=12.5×((7.8+0.2)*1.6)
=12.5*8*1.6
=100*1.6
=160
7.4×5.6+7.4×5.4-74×0.1
=7.4×5.6+7.4×5.4-7.4×1
=7.4×(5.6+5.4-1)
=7.4×10
=74
9.9×9.9+1.99
=9.9×9.9+1+0.99
=9.9×9.9+1+9.9×0.1
=9.9×(9.9+0.1)+1
=9.9×10+1
=100