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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 143 · 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): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  3. 3.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?
  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. 5.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 8, 3 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 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  12. 12.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?
  13. 13.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?
  14. 14.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  15. 15.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  16. 16.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  18. 18.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  19. 19.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?
  20. 20.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?
  21. 21.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  22. 22.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?
  23. 23.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.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?
  28. 28.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  29. 29.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  30. 30.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?
  31. 31.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?
  32. 32.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  34. 34.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  35. 35.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  37. 37.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  40. 40.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 880
  2. 704
  3. 715
  4. 143
  5. 627
  6. 374
  7. 748
  8. 308
  9. 704
  10. 451
  11. 671
  12. 1012
  13. 308
  14. 825
  15. 407
  16. 1056
  17. 495
  18. 572
  19. 770
  20. 418
  21. 1023
  22. 594
  23. 506
  24. 814
  25. 814
  26. 616
  27. 627
  28. 957
  29. 253
  30. 363
  31. 374
  32. 616
  33. 693
  34. 902
  35. 792
  36. 935
  37. 594
  38. 231
  39. 484
  40. 484

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