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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 824 · 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.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?
  2. 2.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  3. 3.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  5. 5.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  21. 21.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?
  22. 22.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?
  23. 23.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  24. 24.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  25. 25.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  26. 26.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  27. 27.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?
  28. 28.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?
  29. 29.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  30. 30.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  32. 32.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  33. 33.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  34. 34.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  36. 36.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  37. 37.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  39. 39.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  40. 40.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 341
  2. 1111
  3. 902
  4. 286
  5. 814
  6. 572
  7. 649
  8. 1089
  9. 759
  10. 858
  11. 682
  12. 935
  13. 704
  14. 561
  15. 968
  16. 495
  17. 671
  18. 253
  19. 726
  20. 715
  21. 957
  22. 693
  23. 495
  24. 1199
  25. 517
  26. 231
  27. 572
  28. 814
  29. 649
  30. 616
  31. 847
  32. 506
  33. 1122
  34. 836
  35. 924
  36. 946
  37. 1122
  38. 506
  39. 627
  40. 451

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