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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 158 · 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  5. 5.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  6. 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  7. 7.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?
  8. 8.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  10. 10.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  11. 11.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  12. 12.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?
  13. 13.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?
  14. 14.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 5, 1 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  20. 20.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  21. 21.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?
  22. 22.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  23. 23.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?
  24. 24.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  25. 25.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?
  26. 26.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  30. 30.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  31. 31.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  38. 38.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  39. 39.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  40. 40.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?

Answer key

  1. 583
  2. 880
  3. 968
  4. 1067
  5. 429
  6. 550
  7. 770
  8. 143
  9. 594
  10. 1287
  11. 506
  12. 605
  13. 704
  14. 451
  15. 847
  16. 737
  17. 616
  18. 363
  19. 781
  20. 231
  21. 484
  22. 847
  23. 594
  24. 726
  25. 374
  26. 792
  27. 308
  28. 671
  29. 836
  30. 693
  31. 1199
  32. 319
  33. 880
  34. 671
  35. 957
  36. 572
  37. 770
  38. 473
  39. 286
  40. 253

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