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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 674 · 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. 1.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  4. 4.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  5. 5.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  8. 8.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  9. 9.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?
  10. 10.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  11. 11.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  15. 15.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  16. 16.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  22. 22.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  28. 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  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. 30.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  32. 32.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?
  33. 33.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  34. 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  36. 36.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?
  37. 37.A leapfrog list starts 5, 8 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 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  40. 40.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =

Answer key

  1. 715
  2. 231
  3. 1177
  4. 374
  5. 891
  6. 143
  7. 308
  8. 1144
  9. 660
  10. 616
  11. 902
  12. 748
  13. 660
  14. 495
  15. 748
  16. 682
  17. 594
  18. 286
  19. 627
  20. 594
  21. 1089
  22. 671
  23. 1056
  24. 462
  25. 814
  26. 473
  27. 902
  28. 957
  29. 759
  30. 495
  31. 550
  32. 143
  33. 1111
  34. 792
  35. 539
  36. 671
  37. 979
  38. 561
  39. 583
  40. 803

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