21 乘法 20 等于多少？

21 × 19 = 399 21 × 21 = 441 21 × 22 = 462 21 × 18 = 378 21 × 23 = 483 21 × 17 = 357 21 × 24 = 504 21 × 16 = 336 20 × 20 = 400 22 × 20 = 440 19 × 20 = 380 23 × 20 = 460 24 × 20 = 480 18 × 20 = 360 25 × 20 = 500 17 × 20 = 340 5 × 84 = 420 6 × 70 = 420 7 × 60 = 420 10 × 42 = 420 12 × 35 = 420 14 × 30 = 420 78 × 72 = 5616 15 × 45 = 675 80 × 19 = 1520 71 × 79 = 5609 10 × 98 = 980 97 × 72 = 6984 90 × 26 = 2340 85 × 83 = 7055