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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 588 · 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 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  2. 2.A leapfrog list starts 3, 8 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  4. 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  5. 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  8. 8.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?
  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 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  12. 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  14. 14.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  15. 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  16. 16.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?
  17. 17.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  20. 20.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  22. 22.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  23. 23.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  24. 24.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?
  25. 25.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  26. 26.A leapfrog list starts 3, 1 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  33. 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  34. 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  37. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  39. 39.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?
  40. 40.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =

Answer key

  1. 1232
  2. 869
  3. 847
  4. 286
  5. 451
  6. 803
  7. 814
  8. 671
  9. 946
  10. 495
  11. 583
  12. 583
  13. 737
  14. 880
  15. 1111
  16. 484
  17. 308
  18. 737
  19. 572
  20. 1287
  21. 231
  22. 660
  23. 1067
  24. 495
  25. 506
  26. 253
  27. 660
  28. 759
  29. 429
  30. 374
  31. 704
  32. 374
  33. 429
  34. 594
  35. 539
  36. 605
  37. 528
  38. 693
  39. 748
  40. 671

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