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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 365 · 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 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  3. 3.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  4. 4.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  7. 7.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?
  8. 8.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  9. 9.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  18. 18.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?
  19. 19.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  20. 20.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  21. 21.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?
  22. 22.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  24. 24.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?
  25. 25.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?
  26. 26.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?
  27. 27.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  32. 32.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  34. 34.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  35. 35.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?
  36. 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  38. 38.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?
  39. 39.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?

Answer key

  1. 682
  2. 1111
  3. 627
  4. 528
  5. 528
  6. 825
  7. 979
  8. 1089
  9. 671
  10. 572
  11. 561
  12. 957
  13. 506
  14. 759
  15. 1023
  16. 858
  17. 594
  18. 286
  19. 583
  20. 451
  21. 418
  22. 649
  23. 407
  24. 594
  25. 671
  26. 451
  27. 858
  28. 319
  29. 253
  30. 1122
  31. 946
  32. 396
  33. 539
  34. 1111
  35. 957
  36. 924
  37. 1001
  38. 792
  39. 880
  40. 1232

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