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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 859 · 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  6. 6.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  7. 7.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  10. 10.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  11. 11.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  13. 13.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?
  14. 14.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?
  15. 15.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  17. 17.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  23. 23.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  27. 27.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  28. 28.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  30. 30.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?
  31. 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  32. 32.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  33. 33.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 7, 7 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  40. 40.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?

Answer key

  1. 528
  2. 968
  3. 759
  4. 517
  5. 715
  6. 726
  7. 198
  8. 1034
  9. 374
  10. 1001
  11. 737
  12. 583
  13. 1012
  14. 451
  15. 737
  16. 891
  17. 748
  18. 946
  19. 363
  20. 550
  21. 231
  22. 803
  23. 1144
  24. 308
  25. 286
  26. 891
  27. 308
  28. 319
  29. 418
  30. 396
  31. 682
  32. 979
  33. 528
  34. 594
  35. 1089
  36. 1001
  37. 341
  38. 506
  39. 143
  40. 737

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