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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 33 · 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 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  3. 3.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?
  4. 4.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  6. 6.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  7. 7.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  8. 8.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  9. 9.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  13. 13.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  15. 15.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?
  16. 16.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  18. 18.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  19. 19.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  20. 20.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.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?
  30. 30.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?
  31. 31.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  32. 32.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 660
  2. 341
  3. 484
  4. 605
  5. 561
  6. 671
  7. 231
  8. 803
  9. 792
  10. 484
  11. 143
  12. 528
  13. 891
  14. 803
  15. 748
  16. 363
  17. 1034
  18. 1111
  19. 1001
  20. 1023
  21. 858
  22. 572
  23. 737
  24. 924
  25. 968
  26. 539
  27. 649
  28. 814
  29. 253
  30. 616
  31. 1056
  32. 968
  33. 319
  34. 396
  35. 1111
  36. 627
  37. 363
  38. 858
  39. 1287
  40. 682

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