题目内容
计算下面各题,带★用简便方法计算.
| 98+2×15 | 75-75÷5 | 720÷8×9 |
| ★450÷25 | ★251-132-68 | ★630÷14÷5. |
考点:整数四则混合运算
专题:计算题
分析:(1)先算乘法,再算加法;
(2)先算除法,再算减法;
(3)按照从左到右的顺序计算;
(4)根据商不变规律进行简算;
(5)根据减法的性质简算;
(6)根据除法的性质简算.
(2)先算除法,再算减法;
(3)按照从左到右的顺序计算;
(4)根据商不变规律进行简算;
(5)根据减法的性质简算;
(6)根据除法的性质简算.
解答:
解:(1)98+2×15
=98+30
=128;
(2)75-75÷5
=75-15
=60;
(3)720÷8×9
=90×9
=810;
(4)450÷25
=(450×4)÷(25×4)
=1800÷100
=18;
(5)251-132-68
=251-(132+68)
=251-200
=51;
(6)630÷14÷5
=630÷(14×5)
=630÷70
=9.
=98+30
=128;
(2)75-75÷5
=75-15
=60;
(3)720÷8×9
=90×9
=810;
(4)450÷25
=(450×4)÷(25×4)
=1800÷100
=18;
(5)251-132-68
=251-(132+68)
=251-200
=51;
(6)630÷14÷5
=630÷(14×5)
=630÷70
=9.
点评:本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.
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