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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 282 · 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. 1.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  2. 2.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  3. 3.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?
  4. 4.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  5. 5.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  6. 6.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?
  7. 7.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  10. 10.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  11. 11.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  12. 12.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  13. 13.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  14. 14.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  19. 19.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?
  20. 20.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  21. 21.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  26. 26.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?
  27. 27.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?
  28. 28.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  29. 29.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.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?
  31. 31.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?
  32. 32.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  33. 33.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?
  34. 34.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  36. 36.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  37. 37.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  38. 38.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?
  39. 39.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 1122
  2. 1287
  3. 792
  4. 957
  5. 858
  6. 1089
  7. 759
  8. 737
  9. 583
  10. 748
  11. 814
  12. 1023
  13. 1001
  14. 946
  15. 671
  16. 759
  17. 462
  18. 847
  19. 1122
  20. 462
  21. 1232
  22. 473
  23. 143
  24. 1287
  25. 968
  26. 660
  27. 363
  28. 341
  29. 825
  30. 594
  31. 396
  32. 506
  33. 319
  34. 484
  35. 319
  36. 429
  37. 825
  38. 638
  39. 737
  40. 528

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