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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 595 · 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, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  9. 9.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  10. 10.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?
  11. 11.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  12. 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  13. 13.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  15. 15.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?
  16. 16.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  18. 18.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?
  19. 19.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  21. 21.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?
  22. 22.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?
  23. 23.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  24. 24.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?
  25. 25.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  27. 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  28. 28.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  29. 29.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?
  30. 30.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  32. 32.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  33. 33.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  34. 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  38. 38.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?
  39. 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  40. 40.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =

Answer key

  1. 891
  2. 1144
  3. 924
  4. 880
  5. 1287
  6. 550
  7. 308
  8. 1067
  9. 814
  10. 693
  11. 759
  12. 660
  13. 198
  14. 946
  15. 198
  16. 847
  17. 759
  18. 627
  19. 594
  20. 1122
  21. 517
  22. 1122
  23. 1287
  24. 748
  25. 748
  26. 1012
  27. 418
  28. 649
  29. 539
  30. 418
  31. 770
  32. 1144
  33. 374
  34. 550
  35. 231
  36. 1023
  37. 737
  38. 803
  39. 253
  40. 1089

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