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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 419 · 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.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?
  2. 2.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  3. 3.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  5. 5.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?
  6. 6.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  12. 12.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  13. 13.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?
  14. 14.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  15. 15.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.A leapfrog list starts 4, 7 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  28. 28.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  31. 31.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  32. 32.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  33. 33.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  34. 34.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?
  35. 35.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  36. 36.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  38. 38.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  39. 39.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  40. 40.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?

Answer key

  1. 506
  2. 638
  3. 693
  4. 891
  5. 814
  6. 418
  7. 1089
  8. 583
  9. 506
  10. 671
  11. 1067
  12. 231
  13. 253
  14. 1177
  15. 627
  16. 715
  17. 836
  18. 968
  19. 660
  20. 286
  21. 858
  22. 726
  23. 1023
  24. 143
  25. 396
  26. 363
  27. 286
  28. 627
  29. 605
  30. 627
  31. 495
  32. 979
  33. 748
  34. 902
  35. 396
  36. 308
  37. 1199
  38. 671
  39. 374
  40. 726

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