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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 870 · 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 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  2. 2.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?
  3. 3.A leapfrog list starts 2, 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.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?
  8. 8.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  9. 9.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  10. 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  11. 11.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?
  12. 12.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  13. 13.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?
  14. 14.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  18. 18.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.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?
  30. 30.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  32. 32.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  33. 33.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  34. 34.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?
  35. 35.A leapfrog list starts 2, 9 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): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  37. 37.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  38. 38.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?
  39. 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  40. 40.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =

Answer key

  1. 143
  2. 363
  3. 198
  4. 1067
  5. 517
  6. 616
  7. 231
  8. 462
  9. 319
  10. 1012
  11. 594
  12. 638
  13. 583
  14. 594
  15. 748
  16. 253
  17. 825
  18. 198
  19. 671
  20. 484
  21. 924
  22. 308
  23. 891
  24. 847
  25. 363
  26. 495
  27. 627
  28. 902
  29. 429
  30. 561
  31. 671
  32. 1199
  33. 550
  34. 143
  35. 902
  36. 682
  37. 935
  38. 308
  39. 583
  40. 517

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