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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 804 · 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 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  5. 5.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?
  6. 6.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  7. 7.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?
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.A leapfrog list starts 2, 2 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  11. 11.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  13. 13.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  14. 14.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?
  15. 15.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  20. 20.A leapfrog list starts 1, 2 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): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  30. 30.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  34. 34.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  37. 37.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  39. 39.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?
  40. 40.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?

Answer key

  1. 462
  2. 924
  3. 286
  4. 1056
  5. 1001
  6. 451
  7. 561
  8. 550
  9. 286
  10. 638
  11. 759
  12. 517
  13. 462
  14. 671
  15. 231
  16. 1089
  17. 616
  18. 682
  19. 407
  20. 231
  21. 462
  22. 792
  23. 726
  24. 781
  25. 869
  26. 594
  27. 1001
  28. 561
  29. 231
  30. 1067
  31. 407
  32. 363
  33. 528
  34. 473
  35. 693
  36. 253
  37. 726
  38. 946
  39. 396
  40. 913

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