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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 55 · 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 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  2. 2.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  6. 6.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  7. 7.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?
  8. 8.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  9. 9.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  10. 10.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  11. 11.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  12. 12.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?
  13. 13.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  15. 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  16. 16.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  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. 18.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  19. 19.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  22. 22.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  23. 23.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?
  24. 24.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?
  25. 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  29. 29.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  30. 30.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  31. 31.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  38. 38.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  39. 39.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?
  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. 858
  2. 759
  3. 550
  4. 726
  5. 781
  6. 803
  7. 396
  8. 693
  9. 1089
  10. 814
  11. 737
  12. 539
  13. 814
  14. 605
  15. 1111
  16. 407
  17. 286
  18. 748
  19. 473
  20. 605
  21. 627
  22. 704
  23. 682
  24. 341
  25. 396
  26. 1122
  27. 308
  28. 902
  29. 451
  30. 770
  31. 880
  32. 902
  33. 484
  34. 869
  35. 748
  36. 308
  37. 902
  38. 957
  39. 704
  40. 924

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