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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 844 · 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. 1.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  7. 7.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  8. 8.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  13. 13.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  14. 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  15. 15.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  16. 16.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?
  17. 17.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  19. 19.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  20. 20.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?
  21. 21.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  22. 22.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  24. 24.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  30. 30.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  31. 31.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  32. 32.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  33. 33.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  38. 38.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 1067
  2. 1056
  3. 1001
  4. 517
  5. 715
  6. 847
  7. 583
  8. 1012
  9. 1199
  10. 528
  11. 253
  12. 1199
  13. 506
  14. 286
  15. 550
  16. 781
  17. 847
  18. 363
  19. 869
  20. 671
  21. 561
  22. 858
  23. 407
  24. 737
  25. 671
  26. 462
  27. 605
  28. 814
  29. 627
  30. 495
  31. 1287
  32. 1144
  33. 583
  34. 506
  35. 781
  36. 253
  37. 671
  38. 231
  39. 957
  40. 1034

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