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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 30 · 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. 1.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  2. 2.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  3. 3.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  4. 4.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?
  5. 5.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  7. 7.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?
  8. 8.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  12. 12.A leapfrog list starts 1, 6 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.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?
  15. 15.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?
  16. 16.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?
  17. 17.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.A leapfrog list starts 6, 4 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 6, 6 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  24. 24.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  25. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  26. 26.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  27. 27.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?
  28. 28.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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. 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  31. 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  32. 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  33. 33.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  35. 35.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?
  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): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =

Answer key

  1. 495
  2. 253
  3. 473
  4. 550
  5. 1034
  6. 638
  7. 539
  8. 429
  9. 451
  10. 869
  11. 462
  12. 583
  13. 517
  14. 924
  15. 671
  16. 561
  17. 594
  18. 1177
  19. 1067
  20. 374
  21. 682
  22. 858
  23. 594
  24. 231
  25. 616
  26. 737
  27. 649
  28. 704
  29. 253
  30. 781
  31. 759
  32. 1001
  33. 253
  34. 726
  35. 341
  36. 308
  37. 737
  38. 418
  39. 957
  40. 1056

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