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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 632 · 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 4, 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  4. 4.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?
  5. 5.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  7. 7.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  8. 8.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  9. 9.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?
  10. 10.A leapfrog list starts 8, 6 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): 9, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  16. 16.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?
  17. 17.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  18. 18.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  19. 19.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?
  20. 20.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  21. 21.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  22. 22.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?
  23. 23.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  28. 28.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  34. 34.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  35. 35.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  36. 36.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?
  37. 37.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 660
  2. 968
  3. 198
  4. 451
  5. 1023
  6. 671
  7. 286
  8. 924
  9. 748
  10. 968
  11. 1287
  12. 528
  13. 231
  14. 1023
  15. 319
  16. 396
  17. 847
  18. 836
  19. 715
  20. 649
  21. 473
  22. 946
  23. 231
  24. 924
  25. 737
  26. 462
  27. 836
  28. 770
  29. 726
  30. 594
  31. 704
  32. 286
  33. 319
  34. 429
  35. 198
  36. 539
  37. 660
  38. 550
  39. 682
  40. 473

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