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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 633 · 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): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  4. 4.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  9. 9.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  10. 10.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?
  11. 11.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  12. 12.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?
  13. 13.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  14. 14.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  15. 15.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  16. 16.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  17. 17.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?
  18. 18.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  21. 21.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  23. 23.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?
  24. 24.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  25. 25.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?
  26. 26.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  27. 27.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  35. 35.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  36. 36.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  38. 38.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  39. 39.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  40. 40.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?

Answer key

  1. 924
  2. 462
  3. 1122
  4. 891
  5. 726
  6. 671
  7. 550
  8. 660
  9. 1177
  10. 803
  11. 671
  12. 1012
  13. 682
  14. 319
  15. 836
  16. 594
  17. 660
  18. 957
  19. 517
  20. 1177
  21. 484
  22. 231
  23. 528
  24. 374
  25. 869
  26. 726
  27. 473
  28. 748
  29. 957
  30. 605
  31. 286
  32. 396
  33. 649
  34. 550
  35. 759
  36. 363
  37. 902
  38. 979
  39. 407
  40. 561

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