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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 931 · 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 3, 5 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  5. 5.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  6. 6.A leapfrog list starts 4, 5 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, 5 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  9. 9.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?
  10. 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  11. 11.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  14. 14.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  24. 24.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  26. 26.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  27. 27.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  28. 28.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  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.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  31. 31.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?
  32. 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  33. 33.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  36. 36.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?
  37. 37.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  38. 38.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  39. 39.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  40. 40.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?

Answer key

  1. 605
  2. 913
  3. 913
  4. 1023
  5. 550
  6. 660
  7. 770
  8. 638
  9. 726
  10. 495
  11. 473
  12. 231
  13. 924
  14. 891
  15. 638
  16. 605
  17. 583
  18. 682
  19. 814
  20. 1111
  21. 462
  22. 374
  23. 693
  24. 363
  25. 660
  26. 506
  27. 616
  28. 1056
  29. 759
  30. 473
  31. 715
  32. 583
  33. 1199
  34. 396
  35. 253
  36. 462
  37. 1111
  38. 418
  39. 572
  40. 539

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