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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 906 · 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 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  3. 3.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  4. 4.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?
  5. 5.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  6. 6.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  8. 8.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 4, 6 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 2, 2 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, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  19. 19.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?
  20. 20.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?
  21. 21.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  24. 24.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?
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  26. 26.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  27. 27.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  28. 28.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?
  29. 29.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  30. 30.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  32. 32.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  33. 33.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?
  34. 34.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  35. 35.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  36. 36.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  38. 38.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  39. 39.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?
  40. 40.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =

Answer key

  1. 429
  2. 594
  3. 583
  4. 748
  5. 286
  6. 363
  7. 462
  8. 1144
  9. 341
  10. 902
  11. 748
  12. 286
  13. 462
  14. 495
  15. 605
  16. 594
  17. 946
  18. 770
  19. 374
  20. 649
  21. 583
  22. 253
  23. 1012
  24. 759
  25. 363
  26. 814
  27. 539
  28. 946
  29. 517
  30. 638
  31. 495
  32. 143
  33. 605
  34. 671
  35. 968
  36. 451
  37. 759
  38. 308
  39. 1001
  40. 880

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