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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 541 · 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. 1.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  2. 2.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  4. 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  5. 5.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  6. 6.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  8. 8.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  10. 10.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  11. 11.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  12. 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  13. 13.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  15. 15.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  16. 16.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  20. 20.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  21. 21.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  22. 22.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  24. 24.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  29. 29.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  37. 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  38. 38.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  39. 39.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 528
  2. 704
  3. 319
  4. 869
  5. 583
  6. 572
  7. 1177
  8. 847
  9. 946
  10. 759
  11. 1089
  12. 902
  13. 550
  14. 979
  15. 935
  16. 880
  17. 451
  18. 1034
  19. 495
  20. 550
  21. 649
  22. 1199
  23. 869
  24. 1023
  25. 583
  26. 1232
  27. 319
  28. 957
  29. 429
  30. 1034
  31. 627
  32. 836
  33. 374
  34. 396
  35. 825
  36. 924
  37. 561
  38. 605
  39. 528
  40. 946

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