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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 995 · 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.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  3. 3.A leapfrog list starts 9, 8 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  6. 6.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  7. 7.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  8. 8.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?
  9. 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  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.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  16. 16.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?
  17. 17.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. What is 11 × the 7th number?
  24. 24.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?
  25. 25.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  27. 27.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  28. 28.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?
  29. 29.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  30. 30.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  32. 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  33. 33.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  34. 34.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  35. 35.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  36. 36.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?
  37. 37.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  38. 38.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?
  39. 39.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  40. 40.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =

Answer key

  1. 407
  2. 517
  3. 1199
  4. 1067
  5. 935
  6. 517
  7. 759
  8. 693
  9. 726
  10. 319
  11. 693
  12. 781
  13. 396
  14. 913
  15. 627
  16. 462
  17. 1111
  18. 495
  19. 737
  20. 374
  21. 396
  22. 1122
  23. 792
  24. 231
  25. 528
  26. 704
  27. 924
  28. 594
  29. 671
  30. 957
  31. 759
  32. 451
  33. 770
  34. 143
  35. 1012
  36. 374
  37. 429
  38. 341
  39. 583
  40. 341

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