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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 683 · 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.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  2. 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  3. 3.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?
  4. 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  6. 6.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  7. 7.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?
  8. 8.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  12. 12.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?
  13. 13.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  16. 16.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  20. 20.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  21. 21.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  22. 22.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  23. 23.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?
  24. 24.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  25. 25.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 8, 2 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): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  31. 31.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  32. 32.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  37. 37.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?
  38. 38.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  39. 39.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?
  40. 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =

Answer key

  1. 1199
  2. 693
  3. 737
  4. 418
  5. 1177
  6. 1122
  7. 946
  8. 429
  9. 561
  10. 253
  11. 1001
  12. 627
  13. 451
  14. 605
  15. 660
  16. 1232
  17. 528
  18. 418
  19. 660
  20. 594
  21. 550
  22. 902
  23. 539
  24. 253
  25. 308
  26. 726
  27. 616
  28. 473
  29. 484
  30. 968
  31. 374
  32. 649
  33. 363
  34. 682
  35. 1012
  36. 1023
  37. 616
  38. 836
  39. 649
  40. 231

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