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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 695 · 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. 1.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  2. 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  3. 3.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?
  4. 4.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  6. 6.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?
  7. 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  8. 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  9. 9.A leapfrog list starts 6, 8 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): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  11. 11.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  12. 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  13. 13.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?
  14. 14.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.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?
  17. 17.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  18. 18.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?
  19. 19.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?
  20. 20.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  29. 29.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?
  30. 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  31. 31.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?
  32. 32.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  33. 33.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?
  34. 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  35. 35.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?
  36. 36.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  37. 37.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  38. 38.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =

Answer key

  1. 1001
  2. 1089
  3. 143
  4. 1232
  5. 638
  6. 473
  7. 968
  8. 858
  9. 1034
  10. 792
  11. 781
  12. 484
  13. 583
  14. 363
  15. 594
  16. 660
  17. 550
  18. 748
  19. 737
  20. 517
  21. 506
  22. 1012
  23. 979
  24. 693
  25. 649
  26. 1067
  27. 341
  28. 407
  29. 319
  30. 374
  31. 616
  32. 847
  33. 979
  34. 506
  35. 902
  36. 847
  37. 561
  38. 726
  39. 253
  40. 759

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