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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 350 · 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  4. 4.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  5. 5.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?
  6. 6.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?
  7. 7.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  8. 8.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?
  9. 9.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  12. 12.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  14. 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  15. 15.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  20. 20.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  21. 21.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  22. 22.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?
  23. 23.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  24. 24.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  25. 25.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?
  26. 26.A leapfrog list starts 4, 4 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 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  30. 30.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?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  33. 33.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  35. 35.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?
  36. 36.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  37. 37.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?
  38. 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  39. 39.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  40. 40.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?

Answer key

  1. 693
  2. 715
  3. 1012
  4. 880
  5. 561
  6. 1232
  7. 1034
  8. 231
  9. 627
  10. 253
  11. 1034
  12. 946
  13. 902
  14. 726
  15. 594
  16. 616
  17. 880
  18. 836
  19. 748
  20. 814
  21. 1287
  22. 583
  23. 1232
  24. 561
  25. 935
  26. 572
  27. 583
  28. 671
  29. 583
  30. 726
  31. 803
  32. 671
  33. 1177
  34. 858
  35. 143
  36. 539
  37. 1144
  38. 1111
  39. 374
  40. 462

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