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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 115 · 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, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  2. 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  3. 3.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?
  4. 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  5. 5.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?
  6. 6.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  8. 8.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  13. 13.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  14. 14.A leapfrog list starts 2, 8 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, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  16. 16.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?
  17. 17.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?
  18. 18.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  19. 19.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  20. 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  21. 21.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  24. 24.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  26. 26.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  27. 27.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  29. 29.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  31. 31.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.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?
  34. 34.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  35. 35.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  36. 36.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?
  37. 37.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?
  38. 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  39. 39.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?
  40. 40.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =

Answer key

  1. 418
  2. 473
  3. 319
  4. 770
  5. 748
  6. 649
  7. 363
  8. 1067
  9. 462
  10. 1067
  11. 495
  12. 682
  13. 726
  14. 814
  15. 506
  16. 429
  17. 638
  18. 671
  19. 836
  20. 847
  21. 253
  22. 660
  23. 869
  24. 715
  25. 374
  26. 143
  27. 286
  28. 451
  29. 308
  30. 462
  31. 1177
  32. 957
  33. 143
  34. 231
  35. 363
  36. 1023
  37. 1089
  38. 451
  39. 341
  40. 561

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