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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 405 · 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 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  3. 3.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?
  4. 4.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  5. 5.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  7. 7.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  8. 8.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?
  9. 9.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  13. 13.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?
  14. 14.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  15. 15.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?
  16. 16.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  17. 17.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  18. 18.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  19. 19.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?
  20. 20.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  21. 21.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 5, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  24. 24.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?
  25. 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  28. 28.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?
  29. 29.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  30. 30.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  32. 32.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  34. 34.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?
  35. 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  36. 36.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?
  37. 37.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?
  38. 38.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?
  39. 39.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  40. 40.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?

Answer key

  1. 627
  2. 550
  3. 495
  4. 1199
  5. 726
  6. 396
  7. 1067
  8. 517
  9. 561
  10. 473
  11. 660
  12. 231
  13. 341
  14. 1012
  15. 825
  16. 902
  17. 451
  18. 627
  19. 759
  20. 418
  21. 979
  22. 539
  23. 363
  24. 968
  25. 957
  26. 1122
  27. 1023
  28. 286
  29. 583
  30. 770
  31. 836
  32. 737
  33. 1056
  34. 836
  35. 638
  36. 1287
  37. 847
  38. 759
  39. 561
  40. 143

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