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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 964 · 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  2. 2.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  5. 5.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  6. 6.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?
  7. 7.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  8. 8.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?
  9. 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  10. 10.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  11. 11.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  12. 12.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  13. 13.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?
  14. 14.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?
  15. 15.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  16. 16.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  17. 17.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  19. 19.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?
  20. 20.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  21. 21.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  22. 22.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  27. 27.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  28. 28.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?
  29. 29.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?
  30. 30.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  31. 31.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  34. 34.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  35. 35.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  37. 37.A leapfrog list starts 9, 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 2, 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 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =

Answer key

  1. 583
  2. 781
  3. 968
  4. 561
  5. 374
  6. 1001
  7. 253
  8. 473
  9. 429
  10. 968
  11. 583
  12. 847
  13. 605
  14. 616
  15. 671
  16. 693
  17. 539
  18. 627
  19. 572
  20. 1111
  21. 407
  22. 616
  23. 913
  24. 319
  25. 693
  26. 1001
  27. 561
  28. 869
  29. 759
  30. 957
  31. 1067
  32. 1287
  33. 957
  34. 704
  35. 836
  36. 198
  37. 1111
  38. 814
  39. 726
  40. 506

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