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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 180 · 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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. 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. 4.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  5. 5.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  8. 8.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  10. 10.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?
  11. 11.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  16. 16.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  17. 17.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?
  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. 19.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  20. 20.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  21. 21.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?
  22. 22.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  31. 31.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  32. 32.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  33. 33.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  35. 35.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  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.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?
  38. 38.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?
  39. 39.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?
  40. 40.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =

Answer key

  1. 957
  2. 341
  3. 1177
  4. 429
  5. 418
  6. 814
  7. 473
  8. 649
  9. 1122
  10. 792
  11. 748
  12. 396
  13. 143
  14. 638
  15. 693
  16. 1111
  17. 231
  18. 682
  19. 198
  20. 847
  21. 363
  22. 1287
  23. 759
  24. 913
  25. 495
  26. 198
  27. 418
  28. 638
  29. 286
  30. 374
  31. 341
  32. 891
  33. 1001
  34. 858
  35. 495
  36. 253
  37. 781
  38. 792
  39. 1287
  40. 968

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