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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 268 · 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): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  2. 2.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?
  3. 3.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  4. 4.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?
  5. 5.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  6. 6.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.A leapfrog list starts 7, 9 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 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  16. 16.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  17. 17.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  22. 22.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.Leapfrog list (each number is the sum of the two before it): 5, 2, 7, 9, 16, 25, 41, 66, 107, 173. What is 11 × the 7th number?
  27. 27.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  28. 28.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?
  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 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.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?
  33. 33.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  35. 35.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?
  36. 36.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  37. 37.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  38. 38.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 682
  2. 143
  3. 286
  4. 143
  5. 143
  6. 517
  7. 880
  8. 1034
  9. 616
  10. 286
  11. 1001
  12. 1177
  13. 814
  14. 924
  15. 231
  16. 517
  17. 935
  18. 605
  19. 638
  20. 528
  21. 1122
  22. 682
  23. 1199
  24. 341
  25. 726
  26. 451
  27. 396
  28. 396
  29. 825
  30. 847
  31. 748
  32. 693
  33. 814
  34. 374
  35. 715
  36. 1023
  37. 946
  38. 946
  39. 1287
  40. 231

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