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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 621 · 40 questions
TalentJR

The trick (Seventh times eleven): A leapfrog list: start with two numbers, then each number is the sum of the two before it, up to 10 numbers. Find the 7th number. Multiply it by 11 (the number with a 0 on the end, plus the number): that is the total of all 10.

NameDateTime takenScore ___ / 40
  1. 1.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  2. 2.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  3. 3.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  9. 9.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  10. 10.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  14. 14.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  15. 15.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  16. 16.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  19. 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  25. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  28. 28.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  31. 31.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  32. 32.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  37. 37.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  39. 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  40. 40.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =

Answer key

  1. 396
  2. 363
  3. 649
  4. 836
  5. 363
  6. 957
  7. 462
  8. 1177
  9. 550
  10. 1199
  11. 1232
  12. 671
  13. 561
  14. 968
  15. 1287
  16. 660
  17. 781
  18. 759
  19. 198
  20. 451
  21. 583
  22. 968
  23. 594
  24. 583
  25. 616
  26. 858
  27. 902
  28. 770
  29. 715
  30. 1144
  31. 143
  32. 660
  33. 935
  34. 1199
  35. 572
  36. 231
  37. 1001
  38. 506
  39. 913
  40. 825

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