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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 596 · 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. 1.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  4. 4.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  5. 5.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  7. 7.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?
  8. 8.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?
  9. 9.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  11. 11.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  17. 17.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  18. 18.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  19. 19.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  20. 20.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  22. 22.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  24. 24.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?
  25. 25.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  26. 26.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  27. 27.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?
  28. 28.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?
  29. 29.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  30. 30.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?
  31. 31.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  32. 32.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  35. 35.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  36. 36.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  38. 38.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  39. 39.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 253
  2. 319
  3. 583
  4. 539
  5. 759
  6. 583
  7. 572
  8. 968
  9. 1232
  10. 198
  11. 803
  12. 231
  13. 748
  14. 143
  15. 418
  16. 1111
  17. 528
  18. 715
  19. 792
  20. 748
  21. 1199
  22. 1089
  23. 341
  24. 880
  25. 396
  26. 583
  27. 759
  28. 374
  29. 1067
  30. 704
  31. 704
  32. 726
  33. 979
  34. 143
  35. 913
  36. 693
  37. 1287
  38. 473
  39. 616
  40. 869

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