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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 346 · 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 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  2. 2.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?
  3. 3.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  4. 4.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  5. 5.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  6. 6.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?
  7. 7.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?
  8. 8.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  9. 9.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?
  10. 10.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?
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.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?
  13. 13.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?
  14. 14.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  15. 15.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  18. 18.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  19. 19.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  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): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  22. 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  23. 23.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  26. 26.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  27. 27.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?
  28. 28.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  30. 30.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  34. 34.A leapfrog list starts 9, 5 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1034
  2. 605
  3. 660
  4. 1122
  5. 594
  6. 682
  7. 759
  8. 451
  9. 869
  10. 1056
  11. 286
  12. 231
  13. 924
  14. 583
  15. 924
  16. 737
  17. 638
  18. 484
  19. 1177
  20. 1287
  21. 814
  22. 671
  23. 682
  24. 616
  25. 825
  26. 198
  27. 473
  28. 968
  29. 902
  30. 550
  31. 198
  32. 1067
  33. 319
  34. 935
  35. 1287
  36. 198
  37. 495
  38. 1144
  39. 946
  40. 341

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