题目内容
计算下面各题.(能简算的要简算)
(1)6.75-2.75÷[10×(9.75-4
)]
(2)(1+
)+(1+
×2)+(1+
×3)+…+(1+
×20).
(1)6.75-2.75÷[10×(9.75-4
1 |
4 |
(2)(1+
19 |
105 |
19 |
105 |
19 |
105 |
19 |
105 |
分析:(1)先算小括号内的,再算中括号内的,然后算括号外的除法,最后算减法;
(2)运用乘法分配律简算.
(2)运用乘法分配律简算.
解答:解:(1)6.75-2.75÷[10×(9.75-4
)],
=6.75-2.75÷[10×(9.75-4.25)],
=6.75-2.75÷[10×5.5],
=6.75-2.75÷55,
=6.75-0.05,
=6.7;
(2)(1+
)×20,
=1×20+
×20,
=20+3
,
=23
.
1 |
4 |
=6.75-2.75÷[10×(9.75-4.25)],
=6.75-2.75÷[10×5.5],
=6.75-2.75÷55,
=6.75-0.05,
=6.7;
(2)(1+
19 |
105 |
=1×20+
19 |
105 |
=20+3
13 |
21 |
=23
13 |
21 |
点评:此题考查了小数、分数的四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算律简便计算.
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