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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 294 · 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  2. 2.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  3. 3.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  6. 6.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?
  7. 7.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  8. 8.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?
  9. 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  10. 10.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?
  11. 11.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?
  12. 12.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  13. 13.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  14. 14.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?
  15. 15.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?
  16. 16.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  17. 17.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  18. 18.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  20. 20.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  21. 21.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  22. 22.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?
  23. 23.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  24. 24.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  25. 25.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  26. 26.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  27. 27.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?
  28. 28.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  29. 29.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  30. 30.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  34. 34.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?
  35. 35.A leapfrog list starts 2, 6 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =

Answer key

  1. 1232
  2. 143
  3. 451
  4. 286
  5. 308
  6. 1034
  7. 506
  8. 484
  9. 649
  10. 847
  11. 462
  12. 1023
  13. 1034
  14. 1199
  15. 583
  16. 286
  17. 1056
  18. 715
  19. 616
  20. 583
  21. 583
  22. 396
  23. 704
  24. 781
  25. 880
  26. 308
  27. 737
  28. 836
  29. 495
  30. 583
  31. 627
  32. 1001
  33. 605
  34. 539
  35. 638
  36. 374
  37. 638
  38. 649
  39. 1144
  40. 770

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