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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 138 · 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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  2. 2.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  3. 3.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.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?
  13. 13.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  15. 15.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?
  16. 16.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  18. 18.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  19. 19.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  20. 20.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?
  21. 21.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?
  22. 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  23. 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  24. 24.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  26. 26.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  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.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  31. 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  34. 34.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  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): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  39. 39.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?
  40. 40.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =

Answer key

  1. 506
  2. 231
  3. 682
  4. 814
  5. 825
  6. 539
  7. 836
  8. 792
  9. 341
  10. 638
  11. 286
  12. 550
  13. 374
  14. 1199
  15. 627
  16. 924
  17. 396
  18. 517
  19. 1001
  20. 572
  21. 231
  22. 671
  23. 1287
  24. 891
  25. 770
  26. 759
  27. 616
  28. 539
  29. 1122
  30. 858
  31. 451
  32. 957
  33. 1012
  34. 704
  35. 286
  36. 759
  37. 1056
  38. 429
  39. 924
  40. 836

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