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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 809 · 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. 1.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  2. 2.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  3. 3.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  8. 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  11. 11.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  12. 12.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?
  13. 13.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  14. 14.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  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.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?
  19. 19.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  25. 25.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?
  26. 26.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  28. 28.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?
  29. 29.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?
  30. 30.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  31. 31.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  32. 32.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  34. 34.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.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?
  37. 37.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  38. 38.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?
  39. 39.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =

Answer key

  1. 198
  2. 847
  3. 198
  4. 1089
  5. 550
  6. 319
  7. 946
  8. 836
  9. 1144
  10. 1287
  11. 451
  12. 726
  13. 528
  14. 1122
  15. 143
  16. 605
  17. 616
  18. 517
  19. 671
  20. 451
  21. 528
  22. 396
  23. 319
  24. 572
  25. 913
  26. 792
  27. 847
  28. 935
  29. 715
  30. 627
  31. 803
  32. 1067
  33. 286
  34. 627
  35. 473
  36. 1089
  37. 253
  38. 1034
  39. 506
  40. 143

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