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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 344 · 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. 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  3. 3.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  4. 4.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  5. 5.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  6. 6.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  7. 7.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?
  8. 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  9. 9.A leapfrog list starts 3, 6 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): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  14. 14.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  18. 18.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  19. 19.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  20. 20.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  26. 26.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  27. 27.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?
  28. 28.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?
  29. 29.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  33. 33.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 319
  2. 396
  3. 594
  4. 451
  5. 605
  6. 1287
  7. 594
  8. 407
  9. 693
  10. 1012
  11. 1089
  12. 715
  13. 1122
  14. 583
  15. 847
  16. 847
  17. 550
  18. 363
  19. 583
  20. 506
  21. 913
  22. 231
  23. 869
  24. 660
  25. 539
  26. 1067
  27. 231
  28. 572
  29. 671
  30. 484
  31. 781
  32. 484
  33. 550
  34. 627
  35. 286
  36. 748
  37. 198
  38. 1034
  39. 231
  40. 979

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