+ = | 1- = | 1÷ = |
- = | × = | 0÷ = |
| 0.9+99×0.9= | ( + )×12= | . |
解: + = , | 1- = , | 1÷ = , |
- = , | × = , | 0÷ =0; |
=0.9×(99+1),
=0.9×100,
=90;
(
+
)×12,=
×12+
×12,=10+3,
=13;
,3x=
×12,3x=9,
3x÷3=9÷3,
x=3.
故答案为:
,
,
,
,
,0,90,13,x=3.分析:0.9+99×0.9运用乘法分配律简算;
(
+
)×12运用乘法分配律简算;
根据比例的性质求解;其它题目根据运算法则直接求解.
点评:本题考查了基本的计算,注意使用运算定律进行简算.
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=
=
-
=
=