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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 856 · 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. 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  2. 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  5. 5.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  10. 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  11. 11.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  13. 13.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?
  14. 14.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  15. 15.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  17. 17.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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. 19.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  20. 20.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  21. 21.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  22. 22.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  26. 26.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  27. 27.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?
  28. 28.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?
  29. 29.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  31. 31.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?
  32. 32.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  33. 33.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  34. 34.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  35. 35.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  36. 36.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  37. 37.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  38. 38.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  40. 40.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =

Answer key

  1. 814
  2. 1177
  3. 869
  4. 407
  5. 616
  6. 561
  7. 1023
  8. 759
  9. 726
  10. 803
  11. 506
  12. 429
  13. 814
  14. 1089
  15. 781
  16. 198
  17. 968
  18. 583
  19. 704
  20. 528
  21. 770
  22. 1012
  23. 968
  24. 803
  25. 649
  26. 891
  27. 550
  28. 319
  29. 341
  30. 682
  31. 616
  32. 583
  33. 682
  34. 1144
  35. 561
  36. 1067
  37. 231
  38. 1177
  39. 715
  40. 847

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