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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 732 · 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. 1.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  3. 3.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  4. 4.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  5. 5.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?
  6. 6.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  13. 13.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?
  14. 14.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  21. 21.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  22. 22.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  23. 23.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  24. 24.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. 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. 28.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  29. 29.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  30. 30.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  32. 32.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  33. 33.A leapfrog list starts 5, 6 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  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. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  40. 40.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?

Answer key

  1. 946
  2. 1012
  3. 473
  4. 737
  5. 583
  6. 638
  7. 231
  8. 781
  9. 198
  10. 1111
  11. 308
  12. 484
  13. 968
  14. 671
  15. 715
  16. 583
  17. 924
  18. 528
  19. 913
  20. 836
  21. 319
  22. 968
  23. 583
  24. 363
  25. 462
  26. 715
  27. 319
  28. 594
  29. 913
  30. 1287
  31. 451
  32. 671
  33. 803
  34. 913
  35. 682
  36. 649
  37. 528
  38. 1067
  39. 847
  40. 935

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