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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 698 · 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  4. 4.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?
  5. 5.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  7. 7.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  8. 8.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  10. 10.A leapfrog list starts 4, 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 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  15. 15.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  16. 16.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  17. 17.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  18. 18.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  19. 19.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?
  20. 20.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?
  21. 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.A leapfrog list starts 1, 6 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): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  28. 28.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?
  29. 29.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  32. 32.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  33. 33.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?
  34. 34.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  35. 35.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?
  36. 36.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  37. 37.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  39. 39.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  40. 40.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?

Answer key

  1. 407
  2. 693
  3. 781
  4. 1056
  5. 671
  6. 737
  7. 781
  8. 858
  9. 935
  10. 396
  11. 407
  12. 715
  13. 825
  14. 759
  15. 198
  16. 946
  17. 957
  18. 704
  19. 1001
  20. 836
  21. 902
  22. 1067
  23. 198
  24. 825
  25. 308
  26. 583
  27. 902
  28. 418
  29. 638
  30. 836
  31. 660
  32. 429
  33. 1287
  34. 616
  35. 308
  36. 693
  37. 682
  38. 1122
  39. 759
  40. 363

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