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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 983 · 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. 1.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  2. 2.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  3. 3.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  4. 4.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  10. 10.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  11. 11.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  13. 13.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  14. 14.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?
  15. 15.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?
  16. 16.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  21. 21.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?
  22. 22.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  26. 26.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?
  27. 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  28. 28.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?
  29. 29.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  37. 37.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  40. 40.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =

Answer key

  1. 759
  2. 704
  3. 517
  4. 847
  5. 1199
  6. 946
  7. 429
  8. 550
  9. 957
  10. 979
  11. 759
  12. 231
  13. 649
  14. 253
  15. 880
  16. 891
  17. 583
  18. 594
  19. 484
  20. 495
  21. 462
  22. 143
  23. 924
  24. 968
  25. 759
  26. 451
  27. 418
  28. 341
  29. 231
  30. 396
  31. 319
  32. 616
  33. 396
  34. 594
  35. 561
  36. 715
  37. 1067
  38. 462
  39. 1111
  40. 198

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