问题
解答题
计算，能简便计算的要简便计算．
|
答案
（1）
+1 30
+1 42
+1 56
+1 72 1 90
=（
-1 5
）+（1 6
-1 6
）+（1 7
-1 7
）+（1 8
-1 8
）+（1 9
-1 9
）1 10
=
-1 5 1 10
=1 10
（2）1998÷19981998 1999
=1998÷1998×1999+1998 1999
=1998×1999 1998×2000
=1999 2000
（3）（9+92+93）×0.01
=[9+9×（9+9×9）]×0.01，
=[9+9×（9+81）]×0.01，
=[9+9×90]×0.01，
=[9+810]×0.01，
=819×0.01，
=8.19
（4）13.5×[1.5×（1.07+1.93）]
=13.5×[1.5×3]
=13.5×4.5
=60.75
（5）
+1 12
×（11 12
-5 2
）1 3
=
+1 12
×11 12 13 6
=
+1 12 143 72
=149 72
（6））（333+667）÷[63×（
-4 7
）]4 9
=1000÷[63×
-63×4 7
]4 9
=1000÷[36-28]
=1000÷8
=125