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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 667 · 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): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  2. 2.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  3. 3.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  4. 4.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?
  5. 5.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  6. 6.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?
  7. 7.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  9. 9.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?
  10. 10.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?
  11. 11.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  16. 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  17. 17.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?
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  21. 21.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  28. 28.A leapfrog list starts 4, 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): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  30. 30.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  32. 32.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 7, 7 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): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  35. 35.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  36. 36.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  40. 40.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?

Answer key

  1. 1111
  2. 781
  3. 935
  4. 627
  5. 407
  6. 605
  7. 539
  8. 924
  9. 935
  10. 528
  11. 143
  12. 561
  13. 715
  14. 594
  15. 198
  16. 638
  17. 363
  18. 638
  19. 803
  20. 143
  21. 374
  22. 462
  23. 880
  24. 1012
  25. 572
  26. 968
  27. 682
  28. 1012
  29. 1232
  30. 253
  31. 638
  32. 1089
  33. 1001
  34. 869
  35. 231
  36. 418
  37. 671
  38. 528
  39. 902
  40. 374

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