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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 917 · 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  2. 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  3. 3.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  5. 5.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?
  6. 6.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  7. 7.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?
  8. 8.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  9. 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  10. 10.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?
  11. 11.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  13. 13.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  16. 16.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  17. 17.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?
  18. 18.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  19. 19.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?
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  23. 23.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?
  24. 24.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  25. 25.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?
  26. 26.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  34. 34.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  36. 36.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?
  37. 37.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  38. 38.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  39. 39.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?
  40. 40.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =

Answer key

  1. 671
  2. 1177
  3. 671
  4. 880
  5. 1001
  6. 858
  7. 759
  8. 1199
  9. 374
  10. 891
  11. 946
  12. 781
  13. 561
  14. 638
  15. 583
  16. 946
  17. 1034
  18. 759
  19. 308
  20. 1122
  21. 1034
  22. 726
  23. 847
  24. 506
  25. 968
  26. 847
  27. 143
  28. 957
  29. 869
  30. 594
  31. 616
  32. 957
  33. 528
  34. 759
  35. 1012
  36. 363
  37. 341
  38. 1111
  39. 605
  40. 407

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