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1.递等式简便运算:3.6X31.4+43.9X6.42.递等式简便运算:5.5X6.6+6.6X7.7+7.7X8.8+8.8X9.9

题目详情
1.递等式简便运算:3.6X31.4+43.9X6.4 2.递等式简便运算:5.5X6.6+6.6X7.7+7.7X8.8+8.8X9.9
▼优质解答
答案和解析
1原式=(10—6.4)X31.4+(31.4+12.5)X6.4
=314—31.4X6.4+31.4X6.4+12.5X6.4
=314+12.5X8X0.8
=314+80
=394
2原式=(5X6+6X7+7X8+8X9)X1.1X1.1
=(30+42+56+72)X1.21
=200X1.21
=242