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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 684 · 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.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  3. 3.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  4. 4.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?
  5. 5.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?
  6. 6.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  7. 7.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  8. 8.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?
  9. 9.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  10. 10.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  11. 11.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 1, 5 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 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  17. 17.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  18. 18.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  19. 19.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  20. 20.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  21. 21.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?
  22. 22.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  23. 23.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?
  24. 24.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  26. 26.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  27. 27.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  28. 28.A leapfrog list starts 5, 9 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): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  30. 30.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  31. 31.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  32. 32.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  33. 33.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  34. 34.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?
  35. 35.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  36. 36.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  37. 37.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?
  38. 38.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?
  39. 39.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.A leapfrog list starts 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 374
  2. 1012
  3. 627
  4. 528
  5. 759
  6. 858
  7. 748
  8. 671
  9. 726
  10. 880
  11. 198
  12. 143
  13. 495
  14. 792
  15. 924
  16. 418
  17. 1111
  18. 1001
  19. 484
  20. 616
  21. 429
  22. 1232
  23. 418
  24. 781
  25. 363
  26. 946
  27. 935
  28. 1067
  29. 726
  30. 781
  31. 704
  32. 396
  33. 671
  34. 308
  35. 638
  36. 286
  37. 143
  38. 814
  39. 847
  40. 913

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