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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 879 · 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. 1.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  2. 2.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?
  3. 3.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  4. 4.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  5. 5.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  6. 6.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  7. 7.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?
  8. 8.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  9. 9.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?
  10. 10.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  12. 12.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  14. 14.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  15. 15.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  16. 16.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?
  17. 17.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  18. 18.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  19. 19.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  22. 22.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  30. 30.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  31. 31.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  34. 34.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?
  35. 35.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  36. 36.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?
  37. 37.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =

Answer key

  1. 1056
  2. 649
  3. 671
  4. 605
  5. 649
  6. 528
  7. 1023
  8. 836
  9. 770
  10. 308
  11. 286
  12. 1144
  13. 429
  14. 1177
  15. 1001
  16. 1199
  17. 781
  18. 1287
  19. 396
  20. 671
  21. 308
  22. 704
  23. 814
  24. 319
  25. 715
  26. 946
  27. 1122
  28. 671
  29. 429
  30. 451
  31. 1034
  32. 583
  33. 627
  34. 539
  35. 858
  36. 649
  37. 847
  38. 1111
  39. 616
  40. 913

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