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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 241 · 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.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  6. 6.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  7. 7.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  10. 10.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  14. 14.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  17. 17.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  18. 18.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?
  19. 19.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  20. 20.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  23. 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  24. 24.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  25. 25.A leapfrog list starts 8, 7 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 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  28. 28.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?
  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): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  31. 31.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?
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.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?
  34. 34.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  35. 35.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  36. 36.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 7, 2 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 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 605
  2. 451
  3. 286
  4. 1001
  5. 396
  6. 1287
  7. 1177
  8. 847
  9. 429
  10. 880
  11. 143
  12. 506
  13. 528
  14. 506
  15. 748
  16. 616
  17. 363
  18. 803
  19. 429
  20. 572
  21. 605
  22. 792
  23. 737
  24. 616
  25. 1056
  26. 891
  27. 253
  28. 550
  29. 715
  30. 1287
  31. 495
  32. 286
  33. 726
  34. 374
  35. 517
  36. 847
  37. 891
  38. 1111
  39. 561
  40. 924

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