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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 942 · 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  5. 5.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  8. 8.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  9. 9.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  13. 13.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  24. 24.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  32. 32.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  33. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  36. 36.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?
  37. 37.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  38. 38.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 1034
  2. 550
  3. 1144
  4. 407
  5. 671
  6. 979
  7. 484
  8. 935
  9. 495
  10. 528
  11. 715
  12. 506
  13. 803
  14. 198
  15. 825
  16. 374
  17. 803
  18. 605
  19. 286
  20. 539
  21. 594
  22. 319
  23. 638
  24. 583
  25. 616
  26. 737
  27. 572
  28. 550
  29. 726
  30. 363
  31. 143
  32. 748
  33. 671
  34. 561
  35. 638
  36. 407
  37. 396
  38. 671
  39. 517
  40. 671

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