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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 300 · 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  5. 5.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?
  6. 6.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  9. 9.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  14. 14.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  15. 15.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  16. 16.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?
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  18. 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  19. 19.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  20. 20.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  21. 21.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?
  22. 22.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  23. 23.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  24. 24.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  26. 26.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  30. 30.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  31. 31.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  32. 32.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?
  33. 33.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  34. 34.A leapfrog list starts 8, 4 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 1, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  37. 37.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?
  38. 38.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  39. 39.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?

Answer key

  1. 1144
  2. 517
  3. 1144
  4. 957
  5. 781
  6. 231
  7. 583
  8. 418
  9. 319
  10. 638
  11. 770
  12. 924
  13. 627
  14. 583
  15. 649
  16. 825
  17. 847
  18. 814
  19. 517
  20. 583
  21. 671
  22. 341
  23. 407
  24. 484
  25. 561
  26. 429
  27. 605
  28. 319
  29. 1177
  30. 143
  31. 506
  32. 803
  33. 781
  34. 792
  35. 671
  36. 363
  37. 561
  38. 253
  39. 550
  40. 253

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