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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 631 · 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.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?
  2. 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  3. 3.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  4. 4.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  6. 6.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  7. 7.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  9. 9.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  11. 11.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?
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  14. 14.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  16. 16.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  19. 19.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?
  20. 20.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  21. 21.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?
  22. 22.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?
  23. 23.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?
  24. 24.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  25. 25.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  26. 26.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  27. 27.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?
  28. 28.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  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): 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. What is 11 × the 7th number?
  31. 31.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  37. 37.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 1232
  2. 814
  3. 671
  4. 253
  5. 858
  6. 979
  7. 572
  8. 1199
  9. 572
  10. 759
  11. 913
  12. 748
  13. 594
  14. 638
  15. 1001
  16. 418
  17. 803
  18. 759
  19. 539
  20. 1089
  21. 561
  22. 979
  23. 715
  24. 143
  25. 726
  26. 847
  27. 1089
  28. 880
  29. 671
  30. 231
  31. 748
  32. 473
  33. 726
  34. 396
  35. 957
  36. 231
  37. 891
  38. 473
  39. 605
  40. 451

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