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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 827 · 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. 1.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  3. 3.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?
  4. 4.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  7. 7.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?
  8. 8.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  9. 9.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?
  10. 10.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  11. 11.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  13. 13.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?
  14. 14.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  16. 16.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?
  17. 17.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  18. 18.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  20. 20.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  21. 21.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  22. 22.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  23. 23.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  24. 24.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  25. 25.A leapfrog list starts 9, 8 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, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  32. 32.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  33. 33.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  38. 38.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?
  39. 39.A leapfrog list starts 8, 7 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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?

Answer key

  1. 726
  2. 286
  3. 528
  4. 847
  5. 451
  6. 649
  7. 902
  8. 1001
  9. 594
  10. 935
  11. 825
  12. 286
  13. 550
  14. 770
  15. 484
  16. 627
  17. 638
  18. 671
  19. 473
  20. 792
  21. 1056
  22. 506
  23. 748
  24. 649
  25. 1199
  26. 539
  27. 143
  28. 891
  29. 704
  30. 869
  31. 781
  32. 1012
  33. 682
  34. 781
  35. 616
  36. 319
  37. 759
  38. 407
  39. 1056
  40. 429

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