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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 245 · 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 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  3. 3.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  4. 4.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  5. 5.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  6. 6.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  7. 7.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?
  8. 8.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  11. 11.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  13. 13.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  14. 14.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?
  15. 15.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  19. 19.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  20. 20.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  26. 26.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  27. 27.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  29. 29.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?
  30. 30.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  31. 31.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  33. 33.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.A leapfrog list starts 7, 2 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): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  37. 37.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?
  38. 38.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =

Answer key

  1. 319
  2. 759
  3. 484
  4. 616
  5. 924
  6. 1122
  7. 341
  8. 935
  9. 968
  10. 1001
  11. 198
  12. 484
  13. 638
  14. 374
  15. 847
  16. 407
  17. 781
  18. 858
  19. 770
  20. 1056
  21. 847
  22. 1177
  23. 759
  24. 286
  25. 1067
  26. 902
  27. 715
  28. 726
  29. 968
  30. 1177
  31. 605
  32. 891
  33. 671
  34. 363
  35. 561
  36. 1287
  37. 638
  38. 1089
  39. 451
  40. 968

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