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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 836 · 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.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  5. 5.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  6. 6.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  7. 7.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?
  8. 8.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?
  9. 9.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  11. 11.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?
  12. 12.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  15. 15.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  16. 16.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  17. 17.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  19. 19.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  20. 20.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?
  21. 21.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  22. 22.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  23. 23.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  24. 24.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  26. 26.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  27. 27.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?
  28. 28.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  29. 29.A leapfrog list starts 5, 4 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): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 3, 3 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, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  34. 34.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  35. 35.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  36. 36.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  37. 37.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?
  38. 38.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?
  39. 39.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =

Answer key

  1. 814
  2. 1111
  3. 803
  4. 671
  5. 1067
  6. 550
  7. 1144
  8. 319
  9. 363
  10. 286
  11. 253
  12. 605
  13. 1144
  14. 627
  15. 1001
  16. 869
  17. 1199
  18. 429
  19. 1122
  20. 671
  21. 583
  22. 143
  23. 858
  24. 462
  25. 495
  26. 781
  27. 198
  28. 935
  29. 627
  30. 891
  31. 143
  32. 429
  33. 880
  34. 715
  35. 847
  36. 594
  37. 1034
  38. 583
  39. 979
  40. 473

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