小学常用π值(新(2)

小学常用π值

1π≈ 3.14 2π≈ 6.28

3π≈ 9.42 4π≈ 12.56

5π≈ 15.7 6π≈ 18.84

7π≈ 21.98 8π≈ 25.12

9π≈ 28.26 10π≈ 31.4

11π≈ 34.54 12π≈37.68

13π≈ 40.82 14π≈ 43.96

15π≈ 47.1 16π≈ 50.24

17π≈ 53.38 18π≈ 56.52

19π≈ 59.66 24π≈ 75.36

25π≈78.5 32π≈100.48

36π≈113.04 45π≈ 141.3

48π≈150.72 64π≈ 200.96

1.5²π=

2.25π≈ 7.065

2.5²π= 6.25π≈ 19.625

常用小数、分数、百分数互化

1/2 = 0.5 = 50%

1/4 = 0.25 = 25% 3/4 = 0.75 = 75%

1/5 = 0.2 = 20% 2/5 = 0.4 = 40%

3/5 = 0.6 = 60% 4/5 = 0.8 = 80%

1/8 = 0.125 = 12.5% 2/8 = 0.25 = 25%

3/8 = 0.375 = 37.5% 5/8 = 0.625 = 62.5%

7/8 = 0.875 = 87.5%

1/3 ≈ 0.333 = 33.3% 2/3≈ 0.667 = 66.7%

1/6 ≈ 0.167 = 16.7% 5/6 ≈ 0.833 = 83.3% 1/9 ≈ 0.111 = 11.1% 2/9 ≈ 0.222 = 22.2%

…

11²=121 12²

=144

1/7 = 0.142857 ≈ 14.3% 13²=169 14²

=196

2/7 = 0.285714 ≈ 28.6% 15²=225 16²

=256

…17²=289 18²=324

19²=361 …