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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 814 · 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.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  5. 5.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  6. 6.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  8. 8.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?
  9. 9.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?
  10. 10.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  16. 16.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  17. 17.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  18. 18.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  21. 21.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  24. 24.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  25. 25.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  26. 26.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?
  27. 27.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  28. 28.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  30. 30.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  31. 31.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  32. 32.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  39. 39.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?

Answer key

  1. 715
  2. 649
  3. 473
  4. 286
  5. 770
  6. 759
  7. 1089
  8. 759
  9. 616
  10. 1012
  11. 605
  12. 869
  13. 583
  14. 550
  15. 638
  16. 913
  17. 143
  18. 198
  19. 825
  20. 418
  21. 902
  22. 737
  23. 693
  24. 506
  25. 671
  26. 913
  27. 726
  28. 1001
  29. 1111
  30. 748
  31. 638
  32. 451
  33. 671
  34. 781
  35. 561
  36. 319
  37. 979
  38. 528
  39. 946
  40. 1056

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