问题
解答题
用递等式计算(能简算的要简算).
|
答案
(1)4
-21 5
+3 4
,5 12
=4
-212 60
+36 60
,25 60
=(4
+12 60
)-225 60
,36 60
=5
-237 60
,36 60
=3
;1 60
(2)9999×36+6666×96,
=3333×3×36+3333×2×96,
=3333×108+3333×192,
=3333×(108+192),
=3333×300,
=999900;
(3)12
-22 5
×32 5
÷23 4
,1 2
=12
-2 5
×12 5
×15 4
,2 5
=
-62 5
,18 5
=
;44 5
(4)3.14×3.2+5.8×3.14+3.14,
=3.14×(3.2+5.8+1),
=3.14×10,
=31.4;
(5)783×
-37.5%+21.8×3.75,3 8
=783×0.375-0.375+218×0.375,
=(783-1+218)×0.375,
=1000×0.375,
=375;
(6)1+2-3-4+5+6-7-8+…-1983-1984+1985+1986,
=1+(2-3-4+5)+(6-7-8+9)…+(1982-1983-1984+1985)+1986,
=1+0+0…+1986,
=1987.