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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 288 · 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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  2. 2.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  3. 3.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?
  4. 4.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  5. 5.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  6. 6.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?
  7. 7.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  8. 8.A leapfrog list starts 8, 6 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 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  11. 11.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  13. 13.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  14. 14.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  15. 15.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  16. 16.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?
  17. 17.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?
  18. 18.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  19. 19.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  20. 20.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?
  21. 21.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?
  22. 22.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  24. 24.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  25. 25.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?
  26. 26.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?
  27. 27.A leapfrog list starts 7, 1 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): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  29. 29.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  30. 30.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?
  31. 31.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?
  32. 32.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  33. 33.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  34. 34.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  35. 35.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?
  36. 36.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  37. 37.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?
  38. 38.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?
  39. 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?

Answer key

  1. 418
  2. 693
  3. 374
  4. 803
  5. 253
  6. 231
  7. 583
  8. 968
  9. 484
  10. 473
  11. 869
  12. 253
  13. 847
  14. 792
  15. 715
  16. 759
  17. 979
  18. 1034
  19. 671
  20. 649
  21. 1111
  22. 1012
  23. 1067
  24. 924
  25. 616
  26. 253
  27. 473
  28. 1034
  29. 1023
  30. 638
  31. 231
  32. 1111
  33. 748
  34. 550
  35. 528
  36. 363
  37. 572
  38. 495
  39. 583
  40. 913

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