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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 408 · 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. 1.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  6. 6.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?
  7. 7.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  8. 8.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?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  11. 11.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?
  12. 12.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  14. 14.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  15. 15.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?
  16. 16.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  17. 17.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?
  18. 18.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  19. 19.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  20. 20.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?
  21. 21.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  22. 22.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  23. 23.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  24. 24.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  29. 29.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  30. 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  31. 31.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  32. 32.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?
  33. 33.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  35. 35.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?
  36. 36.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  37. 37.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?
  38. 38.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  39. 39.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?
  40. 40.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =

Answer key

  1. 1232
  2. 363
  3. 858
  4. 946
  5. 462
  6. 473
  7. 858
  8. 1001
  9. 814
  10. 781
  11. 737
  12. 924
  13. 374
  14. 770
  15. 814
  16. 198
  17. 451
  18. 1023
  19. 682
  20. 759
  21. 1089
  22. 715
  23. 495
  24. 660
  25. 605
  26. 649
  27. 539
  28. 858
  29. 847
  30. 473
  31. 1177
  32. 1023
  33. 396
  34. 946
  35. 638
  36. 880
  37. 1034
  38. 1034
  39. 1232
  40. 319

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