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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 719 · 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 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  3. 3.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  4. 4.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  5. 5.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  6. 6.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?
  7. 7.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  9. 9.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?
  10. 10.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  12. 12.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?
  13. 13.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?
  14. 14.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  15. 15.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  16. 16.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?
  17. 17.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  18. 18.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  19. 19.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?
  20. 20.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?
  21. 21.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?
  22. 22.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  23. 23.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  24. 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  25. 25.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  26. 26.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  27. 27.A leapfrog list starts 9, 7 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): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  29. 29.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  30. 30.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?
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  35. 35.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?
  36. 36.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?
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 550
  2. 341
  3. 308
  4. 363
  5. 198
  6. 649
  7. 847
  8. 946
  9. 143
  10. 451
  11. 946
  12. 594
  13. 1034
  14. 726
  15. 418
  16. 473
  17. 1034
  18. 704
  19. 693
  20. 616
  21. 583
  22. 836
  23. 671
  24. 1111
  25. 1199
  26. 572
  27. 1111
  28. 583
  29. 594
  30. 638
  31. 319
  32. 572
  33. 836
  34. 506
  35. 825
  36. 891
  37. 143
  38. 715
  39. 968
  40. 957

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