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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 307 · 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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  2. 2.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  4. 4.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  5. 5.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  6. 6.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  7. 7.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  8. 8.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 3, 8 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 6, 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  15. 15.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  17. 17.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  18. 18.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  19. 19.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  24. 24.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?
  25. 25.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?
  26. 26.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  28. 28.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?
  29. 29.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  32. 32.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  33. 33.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  36. 36.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  37. 37.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  38. 38.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  39. 39.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 286
  2. 396
  3. 418
  4. 946
  5. 1001
  6. 770
  7. 1177
  8. 1012
  9. 1056
  10. 869
  11. 418
  12. 1122
  13. 825
  14. 847
  15. 627
  16. 1111
  17. 1012
  18. 583
  19. 451
  20. 583
  21. 1056
  22. 616
  23. 935
  24. 319
  25. 517
  26. 693
  27. 660
  28. 814
  29. 1023
  30. 561
  31. 979
  32. 341
  33. 605
  34. 627
  35. 759
  36. 539
  37. 638
  38. 363
  39. 671
  40. 1177

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