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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 329 · 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. 1.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  2. 2.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  3. 3.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  5. 5.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  6. 6.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  7. 7.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?
  8. 8.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  9. 9.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  11. 11.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  12. 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  13. 13.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?
  14. 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  16. 16.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  17. 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  18. 18.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  20. 20.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  23. 23.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?
  24. 24.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  25. 25.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  30. 30.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  31. 31.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  34. 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  35. 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  36. 36.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  39. 39.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?

Answer key

  1. 495
  2. 759
  3. 715
  4. 539
  5. 484
  6. 1287
  7. 363
  8. 968
  9. 484
  10. 374
  11. 792
  12. 935
  13. 396
  14. 627
  15. 341
  16. 429
  17. 572
  18. 836
  19. 847
  20. 979
  21. 1089
  22. 561
  23. 319
  24. 902
  25. 803
  26. 759
  27. 473
  28. 396
  29. 1122
  30. 1232
  31. 847
  32. 286
  33. 770
  34. 550
  35. 605
  36. 1001
  37. 825
  38. 1287
  39. 539
  40. 429

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