小升初数学题：小题的速算与巧算

1、计算4.75-9.64+8.25-1.36.

原式=(4.75+8.25)-(9.64+1.36)

=13-11

=2.

2、计算3.17-2.74+4.7+5.29-0.26+6.3.

原式=(3.71+5.29)+(4.7+6.3)-(2.74+0.26)

=9+11-3

=17.

3、计算(5.25+0.125+5.75)×8.

原式=(5.25+5.75+0.125)×8

=(11+0.125)×8

=11×8+0.125×8

=88+1

=89

4、计算34.5×8.23-34.5+2.77×34.5.

原式=34.5×(8.23-1+2.77)

=34.5×(7.23+2.77)

=34.5×10

=345

5、计算6.25×0.16+264×0.0625+5.2×6.25+0.625×20.

原式=6.25×0.16+2.64×6.25+5.2×6.25+6.25×2

=6.25×(0.16+2.64+5.2+2)

=6.25×10

=62.5

6、计算l0.035×935+0.035+3×0.035+0.07×61×0.5.

原式=l0.035×935+0.035+3×0.035+0.07×0.5×61

=l0.035×935+0.035+3×0.035+0.035×61

=0.035×(935+1+3+61)

=0.035×1000

=35

7、计算19.98×37-199.8×1.9+1998×0.82.

原式=199.8×3.7-199.8×1.9+199.8×8.2

=199.8×(3.7-1.9+8.2)

=199.8×10

=1998

8、计算0.888×125×73+999×3.

原式=0.111×(8×125)×73+111×(9×3)

=111×73+111×27

=111×(73+27)

=111×100

=11100

9、计算1998+199.8+19.98+1.998.

原式=(2000-2)+(200-0.2)+(20-0.02)+(2-0.002)

=2222-2.222

=2222-(10-7.778)

=2222-10+7.778

=2219.778