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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 720 · 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 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  2. 2.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?
  3. 3.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  4. 4.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  5. 5.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  8. 8.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  9. 9.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  18. 18.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  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. 20.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  21. 21.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  23. 23.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  26. 26.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  27. 27.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  29. 29.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  30. 30.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  31. 31.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  32. 32.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  33. 33.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?
  34. 34.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  35. 35.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?
  36. 36.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.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?
  40. 40.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =

Answer key

  1. 858
  2. 902
  3. 594
  4. 847
  5. 308
  6. 528
  7. 1001
  8. 869
  9. 429
  10. 605
  11. 759
  12. 583
  13. 781
  14. 660
  15. 616
  16. 715
  17. 1232
  18. 418
  19. 627
  20. 935
  21. 539
  22. 605
  23. 924
  24. 1232
  25. 715
  26. 473
  27. 847
  28. 561
  29. 1111
  30. 671
  31. 561
  32. 506
  33. 418
  34. 913
  35. 759
  36. 836
  37. 803
  38. 814
  39. 792
  40. 550

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