用递等式计算下列各题,能简算的要简算.①37×40+1035÷23②86.5×2.4÷0.3-690③2.8+[2.4÷(90-60)]④46.5×43.5+43.5×27.5-25×43.5⑤821

题目简介

用递等式计算下列各题,能简算的要简算.①37×40+1035÷23②86.5×2.4÷0.3-690③2.8+[2.4÷(90-60)]④46.5×43.5+43.5×27.5-25×43.5⑤821

题目详情

用递等式计算下列各题,能简算的要简算.
①37×40+1035÷23
②86.5×2.4÷0.3-690
③2.8+[2.4÷(90-60)]
④46.5×43.5+43.5×27.5-25×43.5
8
21
×
3
4
+
7
12
×
4
7

⑥0.4×7+
2
5
×3-0.4×3.
题型:解答题难度:中档来源:不详

答案


①37×40+1035÷23,
=1480+45,
=1525;

②86.5×2.4÷0.3-690,
=207.6÷0.3-690,
=692-690,
=2;

③2.8+[2.4÷(90-60)],
=2.8+[2.4÷30],
=2.8+0.08,
=2.88;

④46.5×43.5+43.5×27.5-25×43.5,
=(46.5+27.5-25)×43.5,
=49×43.5,
=2131.5;

class="stub"8
21
×class="stub"3
4
+class="stub"7
12
×class="stub"4
7

=class="stub"2
7
+class="stub"1
3

=class="stub"13
21


⑥0.4×7+class="stub"2
5
×3-0.4×3,
=0.4×7+0.4×3-0.4×3,
=0.4×(7+3-3),
=0.4×7,
=2.8.

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