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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 711 · 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 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  4. 4.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?
  5. 5.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  6. 6.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  8. 8.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  9. 9.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?
  10. 10.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  11. 11.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  12. 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  13. 13.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?
  14. 14.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  15. 15.A leapfrog list starts 3, 6 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.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?
  18. 18.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?
  19. 19.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?
  20. 20.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  31. 31.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.A leapfrog list starts 7, 2 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, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  35. 35.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 418
  2. 1034
  3. 308
  4. 517
  5. 1012
  6. 968
  7. 583
  8. 759
  9. 319
  10. 759
  11. 902
  12. 583
  13. 517
  14. 1144
  15. 693
  16. 759
  17. 1023
  18. 935
  19. 660
  20. 341
  21. 781
  22. 770
  23. 594
  24. 462
  25. 825
  26. 286
  27. 451
  28. 649
  29. 594
  30. 671
  31. 638
  32. 693
  33. 561
  34. 671
  35. 979
  36. 649
  37. 957
  38. 627
  39. 1089
  40. 759

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