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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 383 · 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. 1.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  2. 2.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?
  3. 3.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  4. 4.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?
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  10. 10.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?
  11. 11.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  12. 12.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  13. 13.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  14. 14.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?
  15. 15.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  16. 16.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  18. 18.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  19. 19.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?
  20. 20.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  21. 21.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?
  22. 22.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  34. 34.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  36. 36.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?
  37. 37.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  40. 40.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?

Answer key

  1. 891
  2. 231
  3. 682
  4. 1001
  5. 572
  6. 517
  7. 341
  8. 308
  9. 737
  10. 803
  11. 363
  12. 726
  13. 143
  14. 748
  15. 198
  16. 1067
  17. 594
  18. 1012
  19. 814
  20. 759
  21. 759
  22. 1023
  23. 528
  24. 649
  25. 374
  26. 231
  27. 792
  28. 143
  29. 682
  30. 869
  31. 759
  32. 957
  33. 594
  34. 605
  35. 946
  36. 946
  37. 451
  38. 847
  39. 473
  40. 539

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