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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 390 · 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. 1.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  2. 2.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  3. 3.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  7. 7.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  13. 13.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  14. 14.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?
  15. 15.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  26. 26.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?
  27. 27.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  29. 29.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  30. 30.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  31. 31.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?
  32. 32.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?
  33. 33.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  38. 38.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  40. 40.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =

Answer key

  1. 198
  2. 858
  3. 594
  4. 649
  5. 561
  6. 825
  7. 1177
  8. 374
  9. 638
  10. 847
  11. 341
  12. 770
  13. 506
  14. 627
  15. 968
  16. 1199
  17. 1199
  18. 539
  19. 583
  20. 539
  21. 1023
  22. 198
  23. 858
  24. 814
  25. 528
  26. 869
  27. 605
  28. 1012
  29. 748
  30. 341
  31. 1122
  32. 363
  33. 462
  34. 1067
  35. 253
  36. 319
  37. 1001
  38. 407
  39. 286
  40. 814

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