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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 209 · 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.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?
  2. 2.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?
  3. 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  8. 8.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  10. 10.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  11. 11.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?
  12. 12.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  14. 14.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?
  15. 15.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  16. 16.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  17. 17.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  18. 18.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  21. 21.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?
  22. 22.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  23. 23.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  24. 24.A leapfrog list starts 4, 9 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): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  28. 28.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  29. 29.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  30. 30.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?
  31. 31.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  32. 32.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.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?
  39. 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  40. 40.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =

Answer key

  1. 418
  2. 143
  3. 583
  4. 836
  5. 451
  6. 572
  7. 374
  8. 550
  9. 1177
  10. 1056
  11. 814
  12. 792
  13. 473
  14. 605
  15. 781
  16. 1023
  17. 517
  18. 660
  19. 924
  20. 902
  21. 847
  22. 671
  23. 594
  24. 1012
  25. 935
  26. 363
  27. 803
  28. 583
  29. 1067
  30. 1023
  31. 913
  32. 682
  33. 528
  34. 407
  35. 143
  36. 341
  37. 528
  38. 539
  39. 319
  40. 726

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