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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 738 · 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. 1.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  2. 2.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?
  3. 3.A leapfrog list starts 5, 3 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.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  6. 6.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.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?
  10. 10.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  12. 12.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?
  13. 13.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  14. 14.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?
  15. 15.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  16. 16.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?
  17. 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  18. 18.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?
  19. 19.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?
  20. 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  21. 21.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  22. 22.A leapfrog list starts 9, 1 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): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  24. 24.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  25. 25.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  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.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?
  28. 28.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  30. 30.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  31. 31.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  32. 32.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.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?
  34. 34.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  35. 35.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  36. 36.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  37. 37.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  38. 38.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?
  39. 39.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  40. 40.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =

Answer key

  1. 946
  2. 407
  3. 539
  4. 286
  5. 1199
  6. 836
  7. 671
  8. 550
  9. 1012
  10. 770
  11. 308
  12. 957
  13. 1111
  14. 418
  15. 814
  16. 572
  17. 418
  18. 319
  19. 198
  20. 451
  21. 583
  22. 583
  23. 781
  24. 374
  25. 1023
  26. 671
  27. 231
  28. 143
  29. 770
  30. 473
  31. 407
  32. 319
  33. 1067
  34. 583
  35. 1012
  36. 319
  37. 594
  38. 704
  39. 539
  40. 572

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