计算下列各题.(能简算的要简算)
1个回答

解题思路:(1)(4)先算乘法,再算加法;

(2)先算乘法,再算减法;

(3)根据减法的性质简算;

(5)运用乘法分配律简算;

(6)先把3.2分解成8×0.4,再运用乘法结合律简算.

(1)19.4×6.1+2.3

=118.34+2.3

=120.64;

(2)5.67×0.21-0.62

=1.1907-0.62

=0.5707;

(3)10-0.72-0.28

=10-(0.72+0.28)

=10-1

=9;

(4)0.8×4.3+1.25

=3.44+1.25

=4.69;

(5)63.8×1.57+1.57×36.2

=(63.8+36.2)×1.57

=100×1.57

=157;

(6)3.2×0.25

=8×0.4×0.25

=8×(0.4×0.25)

=8×0.1

=0.8.

点评:

本题考点: 小数四则混合运算.

考点点评: 本题考查了四则混合运算,注意运算顺序和运算法则,灵活运用所学的运算定律进行简便计算.