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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 862 · 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. 1.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.A leapfrog list starts 3, 9 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 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  13. 13.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  14. 14.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  15. 15.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  17. 17.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  18. 18.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?
  19. 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  20. 20.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?
  21. 21.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  22. 22.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  23. 23.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  25. 25.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?
  26. 26.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  36. 36.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  37. 37.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?
  38. 38.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  39. 39.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?
  40. 40.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =

Answer key

  1. 363
  2. 1001
  3. 396
  4. 1056
  5. 1001
  6. 572
  7. 363
  8. 1056
  9. 616
  10. 957
  11. 759
  12. 858
  13. 1012
  14. 308
  15. 572
  16. 1122
  17. 539
  18. 583
  19. 396
  20. 484
  21. 748
  22. 1232
  23. 836
  24. 671
  25. 803
  26. 253
  27. 253
  28. 726
  29. 869
  30. 319
  31. 902
  32. 319
  33. 913
  34. 935
  35. 803
  36. 429
  37. 143
  38. 825
  39. 198
  40. 143

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