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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 491 · 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 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  3. 3.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  4. 4.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  7. 7.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  8. 8.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  9. 9.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  10. 10.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  16. 16.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?
  17. 17.A leapfrog list starts 1, 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): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  21. 21.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?
  22. 22.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  25. 25.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  26. 26.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?
  27. 27.A leapfrog list starts 8, 3 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 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  30. 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  31. 31.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  32. 32.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  35. 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  36. 36.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  37. 37.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?
  38. 38.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?
  39. 39.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =

Answer key

  1. 968
  2. 583
  3. 638
  4. 913
  5. 594
  6. 803
  7. 759
  8. 726
  9. 462
  10. 363
  11. 605
  12. 396
  13. 671
  14. 286
  15. 671
  16. 198
  17. 583
  18. 429
  19. 935
  20. 286
  21. 583
  22. 231
  23. 660
  24. 506
  25. 308
  26. 1034
  27. 704
  28. 583
  29. 517
  30. 781
  31. 715
  32. 253
  33. 550
  34. 495
  35. 737
  36. 968
  37. 418
  38. 671
  39. 143
  40. 396

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