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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 417 · 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  8. 8.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  9. 9.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  10. 10.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  11. 11.A leapfrog list starts 9, 6 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 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  15. 15.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  16. 16.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?
  17. 17.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?
  18. 18.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  19. 19.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  20. 20.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  22. 22.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  24. 24.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?
  25. 25.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  26. 26.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  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.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  30. 30.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?
  31. 31.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?
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.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?
  34. 34.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.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?
  37. 37.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  39. 39.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  40. 40.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 781
  2. 374
  3. 715
  4. 462
  5. 363
  6. 957
  7. 231
  8. 858
  9. 759
  10. 660
  11. 1023
  12. 1287
  13. 671
  14. 572
  15. 693
  16. 748
  17. 1122
  18. 814
  19. 143
  20. 198
  21. 968
  22. 1067
  23. 363
  24. 1034
  25. 506
  26. 583
  27. 253
  28. 902
  29. 528
  30. 616
  31. 891
  32. 286
  33. 1177
  34. 550
  35. 319
  36. 627
  37. 308
  38. 462
  39. 770
  40. 583

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