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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 125 · 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, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 5, 4 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): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  6. 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  7. 7.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.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?
  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.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?
  12. 12.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?
  13. 13.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  14. 14.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  15. 15.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  17. 17.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  21. 21.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?
  22. 22.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  24. 24.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.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?
  27. 27.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  28. 28.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  29. 29.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  31. 31.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  32. 32.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  33. 33.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  34. 34.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?
  35. 35.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?
  36. 36.A leapfrog list starts 5, 8 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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  38. 38.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  40. 40.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =

Answer key

  1. 704
  2. 726
  3. 1177
  4. 627
  5. 737
  6. 1012
  7. 946
  8. 484
  9. 583
  10. 638
  11. 198
  12. 649
  13. 528
  14. 748
  15. 429
  16. 913
  17. 418
  18. 770
  19. 649
  20. 1177
  21. 374
  22. 715
  23. 891
  24. 407
  25. 550
  26. 1122
  27. 495
  28. 396
  29. 803
  30. 605
  31. 363
  32. 946
  33. 803
  34. 836
  35. 814
  36. 979
  37. 429
  38. 671
  39. 484
  40. 451

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