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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 10 · 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, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  4. 4.A leapfrog list starts 4, 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): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  6. 6.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  7. 7.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  8. 8.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?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  11. 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  12. 12.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?
  13. 13.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  15. 15.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  16. 16.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  20. 20.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  21. 21.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  22. 22.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  24. 24.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?
  25. 25.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  33. 33.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  34. 34.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?
  35. 35.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.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?
  38. 38.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  39. 39.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?
  40. 40.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =

Answer key

  1. 286
  2. 825
  3. 704
  4. 572
  5. 462
  6. 1232
  7. 473
  8. 1023
  9. 671
  10. 1012
  11. 583
  12. 1177
  13. 396
  14. 847
  15. 407
  16. 1177
  17. 1287
  18. 913
  19. 946
  20. 1023
  21. 143
  22. 363
  23. 869
  24. 968
  25. 341
  26. 1023
  27. 308
  28. 880
  29. 1056
  30. 1067
  31. 374
  32. 1232
  33. 1001
  34. 462
  35. 935
  36. 231
  37. 583
  38. 803
  39. 407
  40. 495

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