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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 242 · 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. 1.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  2. 2.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  3. 3.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  14. 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  16. 16.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?
  17. 17.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?
  18. 18.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  19. 19.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  20. 20.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 1, 7 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  24. 24.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  26. 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  27. 27.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  30. 30.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  31. 31.A leapfrog list starts 6, 4 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  37. 37.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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 6, 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?

Answer key

  1. 682
  2. 319
  3. 1144
  4. 726
  5. 572
  6. 946
  7. 594
  8. 286
  9. 748
  10. 704
  11. 748
  12. 429
  13. 231
  14. 407
  15. 418
  16. 396
  17. 286
  18. 539
  19. 770
  20. 693
  21. 462
  22. 671
  23. 561
  24. 979
  25. 550
  26. 1056
  27. 341
  28. 671
  29. 363
  30. 583
  31. 682
  32. 506
  33. 495
  34. 473
  35. 803
  36. 627
  37. 902
  38. 1287
  39. 594
  40. 1056

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