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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 503 · 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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  2. 2.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  3. 3.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?
  4. 4.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  5. 5.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  6. 6.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  7. 7.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  10. 10.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  11. 11.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?
  12. 12.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  13. 13.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?
  14. 14.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  15. 15.A leapfrog list starts 5, 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): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  17. 17.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?
  18. 18.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  19. 19.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  27. 27.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?
  28. 28.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  29. 29.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  33. 33.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  34. 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  35. 35.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. 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.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?
  39. 39.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?
  40. 40.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 286
  2. 341
  3. 231
  4. 583
  5. 308
  6. 583
  7. 748
  8. 583
  9. 770
  10. 726
  11. 671
  12. 814
  13. 880
  14. 319
  15. 539
  16. 847
  17. 583
  18. 484
  19. 748
  20. 451
  21. 836
  22. 946
  23. 374
  24. 594
  25. 231
  26. 495
  27. 616
  28. 803
  29. 583
  30. 506
  31. 847
  32. 946
  33. 869
  34. 143
  35. 198
  36. 572
  37. 902
  38. 968
  39. 759
  40. 968

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