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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 127 · 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. 2.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  3. 3.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  5. 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  6. 6.A leapfrog list starts 2, 8 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, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  15. 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  16. 16.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  22. 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  24. 24.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  26. 26.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  31. 31.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?
  32. 32.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =

Answer key

  1. 594
  2. 286
  3. 847
  4. 913
  5. 451
  6. 814
  7. 913
  8. 759
  9. 726
  10. 847
  11. 627
  12. 253
  13. 1232
  14. 825
  15. 418
  16. 528
  17. 286
  18. 726
  19. 847
  20. 1111
  21. 759
  22. 484
  23. 638
  24. 473
  25. 143
  26. 231
  27. 506
  28. 814
  29. 1199
  30. 374
  31. 341
  32. 660
  33. 968
  34. 495
  35. 319
  36. 1023
  37. 1023
  38. 682
  39. 869
  40. 792

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