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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 169 · 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 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  4. 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  9. 9.A leapfrog list starts 9, 7 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 2, 8 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. 12.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  13. 13.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  14. 14.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  16. 16.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  17. 17.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  22. 22.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?
  23. 23.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.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?
  30. 30.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  31. 31.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?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  34. 34.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?
  35. 35.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?
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  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): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  39. 39.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  40. 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =

Answer key

  1. 374
  2. 836
  3. 979
  4. 418
  5. 792
  6. 341
  7. 1001
  8. 880
  9. 1111
  10. 814
  11. 759
  12. 693
  13. 583
  14. 891
  15. 1111
  16. 572
  17. 1001
  18. 319
  19. 1287
  20. 583
  21. 748
  22. 572
  23. 407
  24. 1144
  25. 396
  26. 539
  27. 550
  28. 902
  29. 682
  30. 869
  31. 781
  32. 484
  33. 759
  34. 308
  35. 935
  36. 198
  37. 737
  38. 506
  39. 594
  40. 726

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