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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 488 · 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): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  8. 8.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  9. 9.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  10. 10.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?
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  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. 14.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 7, 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 5, 4 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, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  21. 21.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?
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  28. 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  29. 29.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?
  30. 30.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  31. 31.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  32. 32.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  33. 33.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?
  34. 34.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  35. 35.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  38. 38.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?
  39. 39.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?
  40. 40.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =

Answer key

  1. 1199
  2. 1001
  3. 429
  4. 957
  5. 583
  6. 803
  7. 484
  8. 1111
  9. 198
  10. 374
  11. 792
  12. 759
  13. 319
  14. 429
  15. 396
  16. 825
  17. 627
  18. 781
  19. 869
  20. 682
  21. 517
  22. 231
  23. 693
  24. 836
  25. 286
  26. 451
  27. 517
  28. 957
  29. 946
  30. 660
  31. 649
  32. 605
  33. 363
  34. 308
  35. 682
  36. 836
  37. 429
  38. 891
  39. 858
  40. 1232

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