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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 971 · 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 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  3. 3.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?
  4. 4.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  6. 6.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?
  7. 7.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  8. 8.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.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?
  10. 10.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  12. 12.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  13. 13.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?
  14. 14.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?
  15. 15.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  17. 17.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?
  18. 18.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  19. 19.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  20. 20.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?
  21. 21.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  22. 22.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  23. 23.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?
  24. 24.A leapfrog list starts 6, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.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?
  26. 26.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?
  27. 27.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  28. 28.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  29. 29.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  30. 30.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?
  31. 31.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  32. 32.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  33. 33.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  35. 35.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  36. 36.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?
  37. 37.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  39. 39.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  40. 40.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?

Answer key

  1. 715
  2. 649
  3. 143
  4. 198
  5. 935
  6. 715
  7. 924
  8. 484
  9. 451
  10. 616
  11. 231
  12. 451
  13. 979
  14. 957
  15. 462
  16. 1122
  17. 605
  18. 1232
  19. 946
  20. 286
  21. 473
  22. 1122
  23. 539
  24. 682
  25. 781
  26. 363
  27. 704
  28. 143
  29. 671
  30. 429
  31. 682
  32. 1001
  33. 473
  34. 374
  35. 308
  36. 748
  37. 660
  38. 968
  39. 880
  40. 143

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