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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 155 · 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. 1.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  2. 2.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?
  3. 3.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  4. 4.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  5. 5.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  10. 10.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?
  11. 11.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  12. 12.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  13. 13.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  14. 14.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  15. 15.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?
  16. 16.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  17. 17.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  18. 18.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?
  19. 19.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  25. 25.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  26. 26.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  27. 27.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  28. 28.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  29. 29.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  31. 31.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?
  32. 32.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  35. 35.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  38. 38.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  39. 39.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?
  40. 40.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 143
  2. 1089
  3. 341
  4. 649
  5. 770
  6. 583
  7. 1122
  8. 231
  9. 946
  10. 825
  11. 583
  12. 473
  13. 759
  14. 594
  15. 957
  16. 286
  17. 1067
  18. 594
  19. 891
  20. 803
  21. 693
  22. 1111
  23. 594
  24. 770
  25. 682
  26. 1111
  27. 737
  28. 1177
  29. 913
  30. 759
  31. 1177
  32. 341
  33. 1144
  34. 495
  35. 517
  36. 814
  37. 473
  38. 484
  39. 924
  40. 473

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