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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 573 · 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  5. 5.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?
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  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.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  12. 12.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  20. 20.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  21. 21.A leapfrog list starts 3, 2 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 7, 8 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): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  24. 24.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?
  25. 25.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  26. 26.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?
  27. 27.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  30. 30.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?
  31. 31.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  32. 32.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  33. 33.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?
  34. 34.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?
  35. 35.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =

Answer key

  1. 594
  2. 1023
  3. 473
  4. 638
  5. 693
  6. 814
  7. 462
  8. 429
  9. 847
  10. 495
  11. 473
  12. 605
  13. 704
  14. 880
  15. 583
  16. 891
  17. 836
  18. 528
  19. 880
  20. 682
  21. 341
  22. 1089
  23. 286
  24. 286
  25. 594
  26. 583
  27. 880
  28. 198
  29. 1144
  30. 638
  31. 968
  32. 649
  33. 671
  34. 418
  35. 946
  36. 451
  37. 1067
  38. 759
  39. 253
  40. 517

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