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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 941 · 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.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?
  2. 2.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?
  3. 3.A leapfrog list starts 4, 5 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 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  6. 6.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  7. 7.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  10. 10.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?
  11. 11.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.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?
  14. 14.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  15. 15.A leapfrog list starts 4, 2 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): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  17. 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  18. 18.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?
  19. 19.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?
  20. 20.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  21. 21.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?
  22. 22.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  23. 23.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?
  24. 24.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  25. 25.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?
  26. 26.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?
  27. 27.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  28. 28.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?
  29. 29.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?
  30. 30.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  31. 31.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  32. 32.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?
  33. 33.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  34. 34.A leapfrog list starts 1, 6 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 8, 4 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 6, 1 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 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  39. 39.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  40. 40.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?

Answer key

  1. 374
  2. 451
  3. 660
  4. 836
  5. 605
  6. 1199
  7. 759
  8. 550
  9. 506
  10. 517
  11. 143
  12. 319
  13. 363
  14. 462
  15. 396
  16. 770
  17. 528
  18. 286
  19. 627
  20. 968
  21. 341
  22. 671
  23. 748
  24. 858
  25. 429
  26. 616
  27. 561
  28. 495
  29. 253
  30. 1111
  31. 869
  32. 858
  33. 693
  34. 583
  35. 792
  36. 418
  37. 924
  38. 660
  39. 143
  40. 913

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