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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 118 · 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, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  4. 4.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?
  5. 5.A leapfrog list starts 4, 1 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): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.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?
  11. 11.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?
  12. 12.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  13. 13.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  14. 14.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  15. 15.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  17. 17.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?
  18. 18.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?
  19. 19.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  20. 20.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  21. 21.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  22. 22.A leapfrog list starts 2, 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): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  24. 24.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  25. 25.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?
  26. 26.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  28. 28.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  29. 29.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  31. 31.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?
  32. 32.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  33. 33.A leapfrog list starts 6, 2 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.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?
  36. 36.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?
  37. 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  38. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  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. 968
  2. 671
  3. 341
  4. 231
  5. 308
  6. 1122
  7. 528
  8. 363
  9. 1089
  10. 462
  11. 726
  12. 539
  13. 319
  14. 1012
  15. 1067
  16. 572
  17. 748
  18. 286
  19. 737
  20. 858
  21. 517
  22. 814
  23. 396
  24. 869
  25. 869
  26. 550
  27. 1023
  28. 484
  29. 836
  30. 429
  31. 935
  32. 715
  33. 506
  34. 374
  35. 682
  36. 880
  37. 913
  38. 759
  39. 528
  40. 143

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