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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 215 · 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. 1.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  3. 3.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  4. 4.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?
  5. 5.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  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. 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  8. 8.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  10. 10.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?
  11. 11.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?
  12. 12.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  13. 13.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?
  14. 14.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  15. 15.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  16. 16.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  19. 19.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  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. 21.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  22. 22.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?
  23. 23.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?
  24. 24.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  27. 27.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  28. 28.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  30. 30.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  31. 31.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?
  32. 32.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  33. 33.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?
  34. 34.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?
  35. 35.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  36. 36.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  38. 38.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?
  39. 39.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  40. 40.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?

Answer key

  1. 671
  2. 1089
  3. 506
  4. 781
  5. 979
  6. 858
  7. 649
  8. 572
  9. 704
  10. 528
  11. 374
  12. 836
  13. 748
  14. 286
  15. 231
  16. 1232
  17. 957
  18. 759
  19. 671
  20. 418
  21. 616
  22. 814
  23. 517
  24. 1111
  25. 286
  26. 671
  27. 880
  28. 715
  29. 715
  30. 550
  31. 671
  32. 583
  33. 704
  34. 638
  35. 968
  36. 1034
  37. 858
  38. 1067
  39. 341
  40. 957

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