计算: (1)-4.2+5.7-8.4+10; (2)6.1-3.7-4.9+1.8; (3)1/3-2/3+1; (4)-1/4+5/6+2/3-1/2.
问题描述:
计算:
(1)-4.2+5.7-8.4+10; (2)6.1-3.7-4.9+1.8;
(3)
-1 3
+1; (4)-2 3
+1 4
+5 6
-2 3
. 1 2
答
(1)原式=(10+5.7)-(4.2+8.4),
=15.7-12.6,
=3.1;
(2)原式=(6.1+1.8)-(3.7+4.9),
=7.9-8.6,
=-0.7;
(3)原式=-
+1=1 3
;2 3
(4)原式=(
+5 6
)-(2 3
+1 4
),1 2
=
-3 2
,3 4
=
.3 4