关于小升初数学题：小数的速算与巧算
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
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