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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 991 · 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.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?
  3. 3.A leapfrog list starts 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.A leapfrog list starts 1, 7 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 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  12. 12.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  15. 15.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?
  16. 16.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  17. 17.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?
  18. 18.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  19. 19.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  20. 20.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  22. 22.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  24. 24.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  25. 25.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  26. 26.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  28. 28.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  29. 29.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  30. 30.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  32. 32.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?
  33. 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  35. 35.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  36. 36.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  39. 39.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  40. 40.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 836
  2. 781
  3. 506
  4. 946
  5. 660
  6. 561
  7. 759
  8. 462
  9. 671
  10. 759
  11. 869
  12. 407
  13. 198
  14. 407
  15. 748
  16. 825
  17. 638
  18. 891
  19. 847
  20. 506
  21. 693
  22. 891
  23. 143
  24. 913
  25. 880
  26. 550
  27. 1089
  28. 1144
  29. 671
  30. 1089
  31. 902
  32. 726
  33. 286
  34. 946
  35. 968
  36. 231
  37. 1111
  38. 869
  39. 957
  40. 781

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