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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 162 · 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): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  2. 2.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  3. 3.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?
  4. 4.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  5. 5.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  7. 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  8. 8.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?
  9. 9.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?
  10. 10.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  11. 11.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  13. 13.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  15. 15.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 1, 4 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): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  22. 22.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?
  23. 23.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?
  24. 24.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  25. 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  26. 26.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  27. 27.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  29. 29.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  30. 30.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  32. 32.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?
  33. 33.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?
  34. 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  35. 35.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  36. 36.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 1177
  2. 957
  3. 693
  4. 1144
  5. 946
  6. 550
  7. 550
  8. 451
  9. 759
  10. 495
  11. 561
  12. 506
  13. 506
  14. 946
  15. 891
  16. 1111
  17. 616
  18. 803
  19. 869
  20. 407
  21. 957
  22. 935
  23. 198
  24. 946
  25. 913
  26. 253
  27. 759
  28. 583
  29. 319
  30. 671
  31. 682
  32. 880
  33. 253
  34. 594
  35. 671
  36. 737
  37. 374
  38. 605
  39. 396
  40. 935

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