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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 536 · 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 9, 7 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 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  5. 5.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  6. 6.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?
  7. 7.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?
  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.A leapfrog list starts 8, 1 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): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  11. 11.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  12. 12.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  13. 13.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  16. 16.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?
  17. 17.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  18. 18.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?
  19. 19.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  22. 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  23. 23.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  24. 24.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?
  25. 25.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  39. 39.A leapfrog list starts 8, 5 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?

Answer key

  1. 1111
  2. 451
  3. 605
  4. 286
  5. 693
  6. 462
  7. 1111
  8. 484
  9. 528
  10. 1001
  11. 979
  12. 748
  13. 1122
  14. 759
  15. 1232
  16. 902
  17. 451
  18. 539
  19. 781
  20. 693
  21. 869
  22. 726
  23. 671
  24. 1199
  25. 198
  26. 616
  27. 374
  28. 363
  29. 704
  30. 825
  31. 616
  32. 583
  33. 605
  34. 957
  35. 418
  36. 726
  37. 759
  38. 1111
  39. 880
  40. 583

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