计算(写出主要过程,其中第①④题简算) ①3.6-2.8+7.4-7.2 ②(1-0.05)÷1.9+0.1 ③4/29×[1-(3/4-3/8)] ④8/17÷23+1/23×9/17.
问题描述:
计算(写出主要过程,其中第①④题简算)
①3.6-2.8+7.4-7.2
②(1-0.05)÷1.9+0.1
③
×[1-(4 29
-3 4
)]3 8
④
÷23+8 17
×1 23
. 9 17
答
①3.6-2.8+7.4-7.2
=(3.6+7.4)-(2.8+7.2)
=11-10
=1;
②(1-0.05)÷1.9+0.1
=0.95÷1.9+0.1
=0.5+0.1
=0.6;
③
×[1-(4 29
-3 4
)]3 8
=
×[1-4 29
]3 8
=
×4 29
5 8
=
;5 58
④
÷23+8 17
×1 23
9 17
=(
+8 17
)×9 17
1 23
=1×
1 23
=
.1 23