四年级上册数学课件-3有趣的算式 22页

沈阳市沈河区朝阳街第一小学 9 9 9 9 9 9 9 9 9 8 8 8 8 8 8 8 8 7 7 7 7 7 7 7 6 6 6 6 6 6 5 5 5 5 5 4 4 4 4 3 3 3 2 2 1 1 12 123 1234 12345 123456 1234567 12345678 123456789 x 8 x 8 x 8 x 8 x 8 x 8 x 8 x 8 x 8 + 1 = + 2 = + 3 = + 4 = + 5 = + 6 = + 7 = + 8 = + 9 = 111111111111111111111111111111111111111111111111111111 1 12 123 1234 12345 123456 1234567 12345678 123456789 x 9 x 9 x 9 x 9  x 9 x 9 x 9 x 9 x 9 + 2 = + 3 = + 4 = + 5 = + 6 = + 7 = + 8 = + 9 = + 10 = x 55 = x 555 = x 5555 = x 55555 = x 555555 = x 5555555 = x 55555555 = 1210 123210 12343210 1234543210 123456543210 123456765432101234567876543210 22 222 2222 22222 222222 2222222 22222222 很炫，是不是？ 88888 888888888 888888 8888888 88888888 888888888 9 98 987 9876 98765 987654 9876543 98765432 x 9 x 9 x 9 x 9 x 9 x 9 x 9 x 9 + 7 = + 6 = + 5 = + 4 = + 3 = + 2 = + 1 = + 0 = 很炫，是不是？ 88888 888888888 888888 8888888 88888888 888888888 9 98 987 9876 98765 987654 9876543 98765432 x 9 x 9 x 9 x 9 x 9 x 9 x 9 x 9 + 7 = + 6 = + 5 = + 4 = + 3 = + 2 = + 1 = + 0 = 1 x 1 = 1 11 x 11 = 1 2 1 111 x 111 = 1 2 3 2 1 1111 x 1111 = 1 2 3 4 3 2 1 11111 x 11111 = 1 2 3 4 5 4 3 2 1 111111 x 111111 = 1 2 3 4 5 6 5 4 3 2 1 1111111 x 1111111 = 1 2 3 4 5 6 7 6 5 4 3 2 1 11111111 x 11111111 = 1 2 3 4 5 6 7 8 7 6 5 4 3 2 1 1 1 1 1 x 1 1 1 1 1 2 1 1 1 2 1 1 2 1 1 1 1 1 1 1 1 1 1 2 3 2 1 1 1 1 x 1 1 1 1 1 1 3 1 1 1 3 1 1 1 1 x 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 3 4 3 2 1 1 1 1 1 4 1 1 1 1 4 …… 乘数有几个 1, 积中间的数字就是几 ? 1 x 1 = 1 11 x 11 = 1 2 1 111 x 111 = 1 2 3 2 1 1111 x 1111 = 1 2 3 4 3 2 1 11111 x 11111 = 1 2 3 4 5 4 3 2 1 111111 x 111111 = 1 2 3 4 5 6 5 4 3 2 1 1111111 x 1111111 = 1 2 3 4 5 6 7 6 5 4 3 2 1 11111111 x 11111111 = 1 2 3 4 5 6 7 8 7 6 5 4 3 2 1 9999 9999 x 9999 9999 = 999 9999 8 000 0000 1 99 x 99 = 99 x (100 － 1) = 9900 － 99 = 9801 9900 － 99 9900 － 99 9 9 0 0 － 9 9 9 8 0 1 0 9 1 0 9 1 9 8 ● 9 8 ● ● 999 x 999 = 999x (1000 － 1) = 999000 － 999 = 998001 999000 － 999 999000 － 999 9 9 9 0 0 0 － 9 9 9 9 9 8 0 0 1 0 9 1 0 9 1 9 8 ● 9 8 ● ● ● 142857 x 1= 142857 x 2= 142857 x 3= 142857 x 4= 142857 285714 428571 571428 1 4 2 8 5 7 奇怪的 142857 1 4 2 8 5 7 ×1 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 1 4 2 8 5 7 ×2 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 1 4 2 8 5 7 ×3 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 1 4 2 8 5 7 ×4 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 1 4 2 8 5 7 ×5 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 1 4 2 8 5 7 ×6 ×1 ×2 ×3 ×4 ×5 ×6 奇怪的 142857 ＋ ＋ = 99 142 857 ＋ = 999 14 28 57 142857×142857=20408122449 20408 122449 ＋ = 142857 142857 x 7=999999