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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 958 · 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. 1.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  7. 7.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  8. 8.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  9. 9.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  14. 14.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  17. 17.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?
  18. 18.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?
  19. 19.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  21. 21.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  23. 23.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  25. 25.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  26. 26.A leapfrog list starts 2, 3 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 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  33. 33.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  34. 34.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  36. 36.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  39. 39.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  40. 40.A leapfrog list starts 4, 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. 792
  2. 902
  3. 1034
  4. 1067
  5. 363
  6. 704
  7. 396
  8. 506
  9. 451
  10. 1089
  11. 231
  12. 880
  13. 814
  14. 858
  15. 1287
  16. 825
  17. 935
  18. 759
  19. 407
  20. 616
  21. 649
  22. 748
  23. 583
  24. 374
  25. 660
  26. 374
  27. 803
  28. 902
  29. 594
  30. 1056
  31. 616
  32. 759
  33. 1012
  34. 583
  35. 891
  36. 1089
  37. 528
  38. 1177
  39. 517
  40. 924

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