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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 790 · 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  3. 3.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  11. 11.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?
  12. 12.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  13. 13.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?
  14. 14.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.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?
  17. 17.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  19. 19.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  20. 20.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  21. 21.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?
  22. 22.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?
  23. 23.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  24. 24.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  25. 25.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  26. 26.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?
  27. 27.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  28. 28.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  29. 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  30. 30.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  32. 32.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  34. 34.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  37. 37.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?
  38. 38.A leapfrog list starts 8, 9 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 506
  2. 1122
  3. 198
  4. 594
  5. 891
  6. 528
  7. 374
  8. 374
  9. 1287
  10. 1177
  11. 1287
  12. 583
  13. 869
  14. 792
  15. 198
  16. 1034
  17. 759
  18. 836
  19. 231
  20. 495
  21. 583
  22. 748
  23. 451
  24. 539
  25. 825
  26. 396
  27. 1144
  28. 770
  29. 319
  30. 253
  31. 286
  32. 495
  33. 616
  34. 484
  35. 605
  36. 902
  37. 946
  38. 1232
  39. 715
  40. 1023

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