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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 436 · 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, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  2. 2.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  3. 3.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  4. 4.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  5. 5.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?
  6. 6.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  7. 7.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  16. 16.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  17. 17.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  18. 18.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  25. 25.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  26. 26.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  27. 27.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?
  28. 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  29. 29.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  31. 31.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  32. 32.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  33. 33.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?
  34. 34.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?
  35. 35.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  36. 36.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  39. 39.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  40. 40.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 429
  2. 1177
  3. 869
  4. 836
  5. 748
  6. 847
  7. 539
  8. 913
  9. 792
  10. 638
  11. 759
  12. 231
  13. 341
  14. 825
  15. 759
  16. 671
  17. 495
  18. 946
  19. 396
  20. 616
  21. 803
  22. 891
  23. 473
  24. 506
  25. 341
  26. 1232
  27. 759
  28. 407
  29. 869
  30. 649
  31. 517
  32. 968
  33. 286
  34. 869
  35. 143
  36. 891
  37. 341
  38. 605
  39. 253
  40. 1034

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