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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 360 · 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. 1.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  4. 4.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  5. 5.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  6. 6.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  8. 8.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?
  9. 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  10. 10.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?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.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?
  17. 17.A leapfrog list starts 5, 8 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): 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  20. 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  21. 21.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?
  22. 22.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  23. 23.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?
  24. 24.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?
  25. 25.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  26. 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  27. 27.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  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): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  30. 30.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  32. 32.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  33. 33.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?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  36. 36.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  37. 37.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?
  38. 38.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?
  39. 39.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  40. 40.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?

Answer key

  1. 671
  2. 374
  3. 660
  4. 737
  5. 825
  6. 770
  7. 682
  8. 462
  9. 231
  10. 583
  11. 1023
  12. 968
  13. 506
  14. 594
  15. 737
  16. 671
  17. 979
  18. 550
  19. 396
  20. 583
  21. 143
  22. 429
  23. 253
  24. 198
  25. 1122
  26. 286
  27. 858
  28. 1232
  29. 616
  30. 550
  31. 1023
  32. 253
  33. 605
  34. 363
  35. 418
  36. 451
  37. 1111
  38. 319
  39. 1067
  40. 770

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