小学奥数公式大全圆周率常取数据3.14×1＝3.143.14×2＝6.283.14×3＝9.423.14×4＝12.563.14×5＝15.73.15×6＝18.843.14×7＝21.983.14×8＝25.123.14×9＝28.26常用特殊数的乘积25×3＝7525×4＝10025×8＝200125×3＝375125×4＝500125×8＝1000625×16＝1000037×3=111常用平方数112=121122=144132=169142=196152=225162=256172=289182=324192=361102=100202=400302=900402=1600502=2500602=36007702=4900802=6400152=225252=625352=1225452=2025552=3025652=4225752=5625852=7225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=0.1253/8=0.3755/8=0.6257/8=0.8751/20=0.053/20=0.157/20=0.359/20=0.4511/20=0.551/25=0.042/25=0.083/25=0.124/25=0.166/25=0.24常用立方数：13=123=833=2743=6453=12563=21673=34383=51293=729
