1、 常用数据及规律1、圆周率常取数据3.1413.14 3.1426.283.1439.423.15618.843.14928.263.14412.563.14721.983.14515.73.14825.122、常用特殊数的乘积25375254100258200 12533756251610000 373=1111254500125810003、常用平方数11=12116=25620=40012=14417=28930=90013=16914=19619=36150=250025=62515=22510=10060=360035=122585=722518=32440=160015=22577
2、0=4900 80=640045=2025 55=3025 65=4225 75=56254、关于常用分数与小数的互化1/2=0.54=0.253/4=0.751/5=0.22/5=0.43/5=0.64/5=0.81/8=0.125 3/8=0.3753/20=0.15 7/20=0.352/25=0.08 3/25=0.125/8=0.6259/20=0.454/25=0.167/8=0.8751/20=0.051/25=0.0411/20=0.556/25=0.24- 1 - 5、常用立方数1=1 2=8 3=27 4=64 5=1256=216 7=343 8=512 9=729- 2 -
