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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 153 · 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): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  2. 2.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  3. 3.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?
  4. 4.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  5. 5.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?
  6. 6.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?
  7. 7.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  8. 8.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?
  9. 9.A leapfrog list starts 2, 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  13. 13.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.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?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  17. 17.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  19. 19.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  20. 20.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  21. 21.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?
  22. 22.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  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. 24.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  25. 25.A leapfrog list starts 9, 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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  31. 31.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  32. 32.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =

Answer key

  1. 143
  2. 374
  3. 1177
  4. 583
  5. 319
  6. 902
  7. 902
  8. 627
  9. 462
  10. 561
  11. 286
  12. 308
  13. 561
  14. 726
  15. 198
  16. 759
  17. 1199
  18. 836
  19. 1232
  20. 649
  21. 924
  22. 363
  23. 682
  24. 1012
  25. 1023
  26. 1001
  27. 418
  28. 1012
  29. 737
  30. 484
  31. 1177
  32. 1089
  33. 1056
  34. 319
  35. 429
  36. 880
  37. 638
  38. 946
  39. 616
  40. 715

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