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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 418 · 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, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  4. 4.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?
  5. 5.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  6. 6.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?
  7. 7.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  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. 17.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  22. 22.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?
  23. 23.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.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?
  25. 25.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  26. 26.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?
  27. 27.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  28. 28.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  29. 29.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?
  30. 30.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?
  31. 31.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  32. 32.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  33. 33.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  37. 37.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 979
  2. 616
  3. 726
  4. 704
  5. 583
  6. 858
  7. 1199
  8. 759
  9. 1067
  10. 517
  11. 594
  12. 484
  13. 935
  14. 913
  15. 572
  16. 1056
  17. 429
  18. 539
  19. 286
  20. 429
  21. 319
  22. 198
  23. 660
  24. 693
  25. 957
  26. 286
  27. 693
  28. 715
  29. 737
  30. 616
  31. 594
  32. 671
  33. 924
  34. 946
  35. 363
  36. 836
  37. 1067
  38. 462
  39. 363
  40. 704

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