题目内容
脱式计算,能简算的要简算:
2+4.6+4+5.4 | 3×2-2×3 |
85×1+2.5÷4 | 1÷[(4-0.005×700)÷1]. |
解:(1)2+4.6+4+5.4,
=(2+4)+(4.6+5.4),
=7+10,
=17;
(2)3×2-2×3,
=2×(3-3),
=×,
=1;
(3)85×1+2.5÷4,
=85×+2.5×,
=102+0.6,
=102.6;
(4)1÷[(4-0.005×700)÷1],
=1÷[(4-3.5)÷1],
=1÷[(4-3)÷1],
=1÷[÷1],
=1÷[×],
=1÷,
=2.
分析:(1)运用加法交换律与结合律简算;
(2)运用乘法分配律简算;
(3)先算除法和乘法,再算加法;
(4)先算小括号内的乘法,再算小括号内的减法,然后算中括号内的除法,最后算括号外的除法.
点评: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.
=(2+4)+(4.6+5.4),
=7+10,
=17;
(2)3×2-2×3,
=2×(3-3),
=×,
=1;
(3)85×1+2.5÷4,
=85×+2.5×,
=102+0.6,
=102.6;
(4)1÷[(4-0.005×700)÷1],
=1÷[(4-3.5)÷1],
=1÷[(4-3)÷1],
=1÷[÷1],
=1÷[×],
=1÷,
=2.
分析:(1)运用加法交换律与结合律简算;
(2)运用乘法分配律简算;
(3)先算除法和乘法,再算加法;
(4)先算小括号内的乘法,再算小括号内的减法,然后算中括号内的除法,最后算括号外的除法.
点评: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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