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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 507 · 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. 1.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  2. 2.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  5. 5.A leapfrog list starts 2, 6 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 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  9. 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  10. 10.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?
  11. 11.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  12. 12.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  14. 14.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?
  15. 15.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 5, 9 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 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 8, 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  28. 28.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  29. 29.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  30. 30.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?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  39. 39.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?

Answer key

  1. 880
  2. 451
  3. 671
  4. 671
  5. 638
  6. 737
  7. 1089
  8. 583
  9. 528
  10. 968
  11. 825
  12. 143
  13. 319
  14. 671
  15. 374
  16. 814
  17. 726
  18. 517
  19. 1023
  20. 1067
  21. 847
  22. 495
  23. 1111
  24. 1144
  25. 704
  26. 616
  27. 1232
  28. 935
  29. 792
  30. 583
  31. 143
  32. 341
  33. 671
  34. 715
  35. 671
  36. 924
  37. 803
  38. 836
  39. 473
  40. 979

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