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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 71 · 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 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  4. 4.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  5. 5.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  6. 6.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  9. 9.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  10. 10.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?
  11. 11.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?
  12. 12.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  13. 13.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  14. 14.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?
  15. 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  16. 16.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?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  22. 22.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  25. 25.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  26. 26.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  31. 31.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  32. 32.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?
  33. 33.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  34. 34.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  36. 36.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?
  37. 37.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  38. 38.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  39. 39.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?
  40. 40.A leapfrog list starts 1, 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. 308
  2. 407
  3. 693
  4. 231
  5. 1089
  6. 649
  7. 1034
  8. 671
  9. 1067
  10. 462
  11. 605
  12. 671
  13. 880
  14. 781
  15. 286
  16. 396
  17. 451
  18. 935
  19. 957
  20. 759
  21. 979
  22. 913
  23. 616
  24. 792
  25. 836
  26. 770
  27. 803
  28. 1287
  29. 814
  30. 583
  31. 506
  32. 1012
  33. 572
  34. 979
  35. 704
  36. 572
  37. 539
  38. 1023
  39. 374
  40. 583

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