脱式计算,能简算的简算. 4.2-1.38+5.8-3.62 0.125×0.25×32 2÷2/3-2/3÷2 90.5×99+90.5.

问题描述:

脱式计算,能简算的简算.
4.2-1.38+5.8-3.62          
 0.125×0.25×32

2
3
-
2
3
÷2             
 90.5×99+90.5.

(1)4.2-1.38+5.8-3.62   
=4.2+5.8-(1.38+3.62)
=10-5
=5;
(2)0.125×0.25×32
=0.125×0.25×8×4
=(0.125×8)×(0.25×4)
=1;
(3)2÷

2
3
-
2
3
÷2  
=2×
3
2
-
2
3
×
1
2

=3-
1
3

=2
2
3

(4)90.5×99+90.5
=90.5×(99+1)
=90.5×100
=9050;
故答案为2.8;1;2
2
3
;9050.