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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 147 · 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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  7. 7.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  9. 9.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.A leapfrog list starts 4, 5 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): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  13. 13.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?
  14. 14.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  15. 15.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?
  16. 16.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  17. 17.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  18. 18.A leapfrog list starts 2, 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  20. 20.A leapfrog list starts 5, 4 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  22. 22.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  23. 23.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?
  24. 24.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?
  25. 25.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  26. 26.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  27. 27.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?
  28. 28.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  31. 31.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  32. 32.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?
  33. 33.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  36. 36.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?
  37. 37.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  38. 38.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  39. 39.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  40. 40.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =

Answer key

  1. 671
  2. 1012
  3. 671
  4. 341
  5. 737
  6. 517
  7. 198
  8. 847
  9. 616
  10. 231
  11. 660
  12. 198
  13. 649
  14. 1122
  15. 693
  16. 913
  17. 1012
  18. 726
  19. 671
  20. 627
  21. 869
  22. 484
  23. 902
  24. 759
  25. 759
  26. 671
  27. 605
  28. 1034
  29. 968
  30. 979
  31. 583
  32. 572
  33. 418
  34. 583
  35. 572
  36. 539
  37. 143
  38. 341
  39. 1067
  40. 924

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