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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 259 · 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. 1.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  8. 8.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?
  9. 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  11. 11.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  12. 12.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?
  13. 13.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  14. 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.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?
  17. 17.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  18. 18.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 6, 2 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): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  30. 30.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?
  31. 31.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?
  32. 32.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  35. 35.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 2, 9 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 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  40. 40.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1287
  2. 418
  3. 462
  4. 407
  5. 528
  6. 781
  7. 286
  8. 143
  9. 726
  10. 1089
  11. 418
  12. 363
  13. 517
  14. 143
  15. 198
  16. 737
  17. 308
  18. 374
  19. 759
  20. 814
  21. 869
  22. 671
  23. 462
  24. 748
  25. 748
  26. 506
  27. 836
  28. 583
  29. 253
  30. 946
  31. 506
  32. 759
  33. 143
  34. 605
  35. 1232
  36. 913
  37. 902
  38. 1199
  39. 253
  40. 880

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