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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 599 · 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): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  5. 5.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  6. 6.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  8. 8.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  9. 9.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?
  10. 10.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  12. 12.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  13. 13.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  15. 15.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?
  16. 16.A leapfrog list starts 5, 9 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, 8, 13, 21, 34, 55, 89, 144, 233, 377. 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.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?
  20. 20.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?
  21. 21.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  24. 24.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  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.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.A leapfrog list starts 2, 3 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): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  29. 29.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  30. 30.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?
  31. 31.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  32. 32.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?
  33. 33.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  34. 34.A leapfrog list starts 8, 1 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 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  37. 37.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?
  38. 38.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =

Answer key

  1. 1056
  2. 1232
  3. 759
  4. 1199
  5. 902
  6. 462
  7. 1001
  8. 891
  9. 781
  10. 572
  11. 781
  12. 341
  13. 880
  14. 561
  15. 671
  16. 1067
  17. 979
  18. 286
  19. 759
  20. 484
  21. 253
  22. 594
  23. 407
  24. 748
  25. 968
  26. 583
  27. 374
  28. 748
  29. 627
  30. 396
  31. 1287
  32. 473
  33. 935
  34. 528
  35. 693
  36. 704
  37. 1122
  38. 429
  39. 616
  40. 847

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