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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 561 · 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, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  6. 6.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  7. 7.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  9. 9.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  17. 17.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  18. 18.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  21. 21.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  27. 27.A leapfrog list starts 9, 5 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 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  30. 30.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?
  31. 31.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  34. 34.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  36. 36.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  38. 38.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  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. 40.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =

Answer key

  1. 550
  2. 1012
  3. 605
  4. 1012
  5. 1089
  6. 396
  7. 803
  8. 550
  9. 825
  10. 869
  11. 671
  12. 880
  13. 429
  14. 451
  15. 869
  16. 605
  17. 374
  18. 1089
  19. 1232
  20. 143
  21. 363
  22. 308
  23. 583
  24. 286
  25. 858
  26. 418
  27. 935
  28. 528
  29. 649
  30. 979
  31. 1122
  32. 649
  33. 1177
  34. 781
  35. 748
  36. 495
  37. 715
  38. 682
  39. 847
  40. 231

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