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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 21 · 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): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  3. 3.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  7. 7.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  8. 8.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  9. 9.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?
  10. 10.A leapfrog list starts 8, 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, 4 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 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 3, 1 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  17. 17.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?
  18. 18.A leapfrog list starts 5, 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): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  20. 20.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?
  21. 21.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  22. 22.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  23. 23.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  28. 28.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?
  29. 29.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?
  30. 30.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  31. 31.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?
  32. 32.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  35. 35.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?
  36. 36.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  37. 37.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  38. 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.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?

Answer key

  1. 803
  2. 792
  3. 891
  4. 517
  5. 418
  6. 396
  7. 605
  8. 308
  9. 605
  10. 1144
  11. 682
  12. 935
  13. 869
  14. 198
  15. 253
  16. 308
  17. 143
  18. 451
  19. 924
  20. 286
  21. 704
  22. 319
  23. 286
  24. 638
  25. 671
  26. 737
  27. 847
  28. 583
  29. 1122
  30. 583
  31. 429
  32. 825
  33. 715
  34. 693
  35. 627
  36. 484
  37. 968
  38. 1067
  39. 616
  40. 671

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