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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 404 · 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.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?
  2. 2.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  3. 3.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  4. 4.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?
  5. 5.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  7. 7.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  8. 8.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?
  9. 9.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  10. 10.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  11. 11.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  15. 15.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  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. 18.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  23. 23.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  24. 24.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  27. 27.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  28. 28.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?
  29. 29.A leapfrog list starts 6, 3 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, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  33. 33.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  36. 36.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?
  37. 37.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  39. 39.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 605
  2. 473
  3. 946
  4. 737
  5. 869
  6. 517
  7. 671
  8. 1089
  9. 308
  10. 462
  11. 957
  12. 891
  13. 143
  14. 1056
  15. 1023
  16. 1177
  17. 451
  18. 792
  19. 550
  20. 627
  21. 374
  22. 319
  23. 407
  24. 143
  25. 902
  26. 660
  27. 913
  28. 583
  29. 594
  30. 319
  31. 1012
  32. 638
  33. 671
  34. 880
  35. 792
  36. 143
  37. 715
  38. 1012
  39. 847
  40. 715

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