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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 439 · 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. 1.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  2. 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  3. 3.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?
  4. 4.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  5. 5.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  8. 8.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  10. 10.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  11. 11.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?
  12. 12.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  13. 13.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  20. 20.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?
  21. 21.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  24. 24.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  25. 25.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  26. 26.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  27. 27.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  30. 30.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  32. 32.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  34. 34.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?
  35. 35.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  38. 38.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  39. 39.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?
  40. 40.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =

Answer key

  1. 319
  2. 770
  3. 836
  4. 308
  5. 583
  6. 693
  7. 715
  8. 473
  9. 1232
  10. 693
  11. 539
  12. 363
  13. 484
  14. 759
  15. 341
  16. 880
  17. 1232
  18. 605
  19. 308
  20. 704
  21. 880
  22. 638
  23. 550
  24. 451
  25. 869
  26. 539
  27. 528
  28. 979
  29. 341
  30. 671
  31. 803
  32. 1144
  33. 792
  34. 781
  35. 308
  36. 1023
  37. 660
  38. 1067
  39. 396
  40. 418

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