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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 356 · 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, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  3. 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  4. 4.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?
  5. 5.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  6. 6.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  7. 7.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  8. 8.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  10. 10.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  12. 12.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  13. 13.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  14. 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  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.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  18. 18.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  19. 19.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?
  20. 20.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?
  21. 21.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  22. 22.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  23. 23.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?
  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.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  27. 27.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  31. 31.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?
  32. 32.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  34. 34.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?
  35. 35.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  36. 36.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?
  37. 37.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  38. 38.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?
  39. 39.A leapfrog list starts 4, 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): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?

Answer key

  1. 869
  2. 407
  3. 506
  4. 319
  5. 1177
  6. 286
  7. 880
  8. 484
  9. 880
  10. 363
  11. 143
  12. 935
  13. 341
  14. 858
  15. 671
  16. 616
  17. 1067
  18. 231
  19. 319
  20. 473
  21. 803
  22. 528
  23. 737
  24. 913
  25. 968
  26. 605
  27. 803
  28. 1287
  29. 1034
  30. 1012
  31. 1199
  32. 407
  33. 649
  34. 286
  35. 902
  36. 957
  37. 517
  38. 1023
  39. 572
  40. 693

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