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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 533 · 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 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  2. 2.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  3. 3.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  8. 8.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  22. 22.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  23. 23.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  24. 24.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  25. 25.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?
  26. 26.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  27. 27.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?
  28. 28.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  29. 29.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?
  30. 30.A leapfrog list starts 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  33. 33.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?
  34. 34.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  39. 39.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?
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?

Answer key

  1. 847
  2. 506
  3. 407
  4. 891
  5. 583
  6. 759
  7. 286
  8. 913
  9. 1199
  10. 649
  11. 1001
  12. 396
  13. 451
  14. 803
  15. 462
  16. 550
  17. 924
  18. 495
  19. 649
  20. 1067
  21. 891
  22. 308
  23. 143
  24. 539
  25. 638
  26. 781
  27. 1144
  28. 1199
  29. 1012
  30. 671
  31. 616
  32. 253
  33. 583
  34. 1001
  35. 836
  36. 429
  37. 363
  38. 374
  39. 605
  40. 1122

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