3.14×1＝3.14
3.14×2＝6.28
3.14×3＝9.42
3.14×4＝12.56
3.14×5＝15.7
3.14×6＝18.84
3.14×7＝21.98
3.14×8＝25.12
3.14×9＝28.26
11 × 11 = 121
12 × 12 = 144
13 × 13 = 169
14 × 14 = 196
15 × 15 = 225
16 × 16 = 256
17 × 17 = 289
18 × 18 = 324
19 × 19 = 361
20 × 20 = 400