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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 269 · 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 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  3. 3.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?
  4. 4.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  5. 5.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  7. 7.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  8. 8.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.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?
  11. 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  12. 12.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?
  13. 13.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  14. 14.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  15. 15.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  16. 16.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  17. 17.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  19. 19.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?
  20. 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  21. 21.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  24. 24.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  25. 25.A leapfrog list starts 5, 3 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 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  29. 29.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  30. 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  31. 31.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?
  32. 32.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?
  33. 33.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  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. 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  36. 36.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?
  37. 37.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?
  38. 38.A leapfrog list starts 1, 1 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 9, 1 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, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?

Answer key

  1. 1177
  2. 1089
  3. 748
  4. 759
  5. 396
  6. 253
  7. 484
  8. 627
  9. 682
  10. 374
  11. 583
  12. 143
  13. 605
  14. 429
  15. 561
  16. 737
  17. 363
  18. 1056
  19. 363
  20. 341
  21. 396
  22. 847
  23. 660
  24. 286
  25. 539
  26. 825
  27. 902
  28. 363
  29. 1232
  30. 1111
  31. 286
  32. 198
  33. 715
  34. 473
  35. 638
  36. 308
  37. 660
  38. 143
  39. 583
  40. 869

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