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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 603 · 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, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  6. 6.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  7. 7.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  10. 10.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  11. 11.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  12. 12.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  13. 13.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?
  14. 14.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  17. 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  18. 18.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  19. 19.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  20. 20.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  21. 21.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  23. 23.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  30. 30.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  31. 31.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  32. 32.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?
  33. 33.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  34. 34.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  40. 40.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =

Answer key

  1. 1111
  2. 539
  3. 374
  4. 341
  5. 814
  6. 792
  7. 407
  8. 253
  9. 957
  10. 880
  11. 726
  12. 418
  13. 682
  14. 143
  15. 605
  16. 759
  17. 528
  18. 286
  19. 451
  20. 748
  21. 671
  22. 616
  23. 627
  24. 308
  25. 517
  26. 1056
  27. 319
  28. 627
  29. 924
  30. 341
  31. 946
  32. 825
  33. 506
  34. 737
  35. 660
  36. 979
  37. 847
  38. 1111
  39. 913
  40. 539

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