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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 166 · 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, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  10. 10.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  11. 11.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?
  12. 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  13. 13.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?
  14. 14.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  15. 15.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?
  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. 17.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  21. 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  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.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?
  24. 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  25. 25.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  26. 26.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?
  27. 27.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?
  28. 28.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  31. 31.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?
  32. 32.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  33. 33.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?
  34. 34.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  37. 37.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?
  38. 38.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =

Answer key

  1. 539
  2. 770
  3. 1199
  4. 550
  5. 781
  6. 143
  7. 759
  8. 484
  9. 374
  10. 396
  11. 506
  12. 1067
  13. 407
  14. 319
  15. 858
  16. 616
  17. 737
  18. 550
  19. 473
  20. 451
  21. 616
  22. 1122
  23. 1111
  24. 1111
  25. 429
  26. 814
  27. 781
  28. 1232
  29. 1287
  30. 286
  31. 319
  32. 484
  33. 671
  34. 682
  35. 825
  36. 605
  37. 682
  38. 462
  39. 737
  40. 583

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