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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 661 · 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 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  4. 4.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?
  5. 5.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  11. 11.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  16. 16.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?
  17. 17.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  18. 18.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  19. 19.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  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. 31.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  33. 33.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?
  34. 34.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  35. 35.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  37. 37.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  38. 38.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  39. 39.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  40. 40.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 638
  2. 407
  3. 759
  4. 374
  5. 374
  6. 781
  7. 429
  8. 770
  9. 418
  10. 517
  11. 858
  12. 583
  13. 638
  14. 308
  15. 616
  16. 594
  17. 286
  18. 1144
  19. 605
  20. 1089
  21. 231
  22. 1287
  23. 726
  24. 616
  25. 528
  26. 517
  27. 1023
  28. 286
  29. 715
  30. 561
  31. 308
  32. 143
  33. 814
  34. 671
  35. 550
  36. 473
  37. 715
  38. 1122
  39. 693
  40. 1177

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