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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 594 · 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): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  5. 5.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  6. 6.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  7. 7.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.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?
  15. 15.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  17. 17.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  18. 18.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  19. 19.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?
  20. 20.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?
  21. 21.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  22. 22.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?
  23. 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  24. 24.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?
  25. 25.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  27. 27.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  28. 28.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  29. 29.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  31. 31.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?
  32. 32.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  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.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  36. 36.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  37. 37.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  38. 38.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  39. 39.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 924
  2. 1232
  3. 605
  4. 506
  5. 462
  6. 374
  7. 418
  8. 319
  9. 1177
  10. 374
  11. 231
  12. 737
  13. 1232
  14. 253
  15. 1111
  16. 462
  17. 737
  18. 1287
  19. 627
  20. 946
  21. 682
  22. 143
  23. 671
  24. 979
  25. 1034
  26. 528
  27. 1122
  28. 748
  29. 836
  30. 1144
  31. 1122
  32. 473
  33. 539
  34. 583
  35. 726
  36. 803
  37. 825
  38. 451
  39. 1023
  40. 671

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