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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 478 · 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. 1.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  2. 2.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  3. 3.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  5. 5.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  6. 6.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?
  7. 7.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  8. 8.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  17. 17.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  18. 18.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  19. 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  20. 20.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  22. 22.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  23. 23.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?
  24. 24.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?
  25. 25.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  26. 26.A leapfrog list starts 2, 1 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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  28. 28.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?
  29. 29.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  30. 30.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.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?
  34. 34.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  35. 35.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?
  36. 36.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  37. 37.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  39. 39.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?
  40. 40.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?

Answer key

  1. 627
  2. 198
  3. 407
  4. 671
  5. 1287
  6. 484
  7. 924
  8. 1012
  9. 671
  10. 1034
  11. 1001
  12. 473
  13. 803
  14. 286
  15. 231
  16. 726
  17. 583
  18. 143
  19. 1232
  20. 792
  21. 253
  22. 374
  23. 341
  24. 1177
  25. 484
  26. 198
  27. 671
  28. 1232
  29. 946
  30. 1144
  31. 748
  32. 869
  33. 539
  34. 1122
  35. 429
  36. 605
  37. 781
  38. 770
  39. 561
  40. 550

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