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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 72 · 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. 1.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  2. 2.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  4. 4.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?
  5. 5.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  6. 6.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  7. 7.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?
  8. 8.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  9. 9.A leapfrog list starts 9, 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 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  13. 13.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  14. 14.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?
  15. 15.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  16. 16.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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.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?
  19. 19.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  21. 21.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?
  22. 22.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  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.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?
  26. 26.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  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.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  31. 31.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?
  32. 32.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  33. 33.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?
  34. 34.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  36. 36.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  37. 37.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?
  38. 38.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 836
  2. 1001
  3. 638
  4. 759
  5. 451
  6. 462
  7. 770
  8. 374
  9. 583
  10. 902
  11. 253
  12. 825
  13. 198
  14. 374
  15. 407
  16. 1067
  17. 594
  18. 363
  19. 957
  20. 308
  21. 902
  22. 561
  23. 363
  24. 1232
  25. 418
  26. 396
  27. 1111
  28. 1122
  29. 814
  30. 704
  31. 1287
  32. 319
  33. 198
  34. 1012
  35. 473
  36. 418
  37. 396
  38. 814
  39. 748
  40. 803

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