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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 261 · 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 4, 9 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): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  9. 9.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  10. 10.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?
  11. 11.A leapfrog list starts 5, 3 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): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  13. 13.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  14. 14.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  15. 15.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  16. 16.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?
  17. 17.A leapfrog list starts 9, 9 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 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  25. 25.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  29. 29.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  30. 30.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  31. 31.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?
  32. 32.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?
  33. 33.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. 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 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 1012
  2. 1067
  3. 759
  4. 891
  5. 528
  6. 847
  7. 517
  8. 143
  9. 473
  10. 308
  11. 539
  12. 561
  13. 1001
  14. 836
  15. 759
  16. 759
  17. 1287
  18. 781
  19. 902
  20. 891
  21. 572
  22. 308
  23. 880
  24. 858
  25. 682
  26. 825
  27. 231
  28. 671
  29. 286
  30. 528
  31. 517
  32. 605
  33. 517
  34. 1012
  35. 1089
  36. 847
  37. 913
  38. 935
  39. 682
  40. 1056

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