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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 626 · 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): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  2. 2.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  3. 3.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?
  4. 4.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  5. 5.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?
  6. 6.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  8. 8.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?
  9. 9.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  10. 10.A leapfrog list starts 6, 3 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 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.Leapfrog list (each number is the sum of the two before it): 8, 4, 12, 16, 28, 44, 72, 116, 188, 304. 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 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  20. 20.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  22. 22.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  23. 23.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?
  24. 24.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  25. 25.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?
  26. 26.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  27. 27.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?
  28. 28.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  29. 29.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?
  30. 30.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  31. 31.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?
  32. 32.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  37. 37.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  38. 38.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  39. 39.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. 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. 858
  2. 1232
  3. 583
  4. 781
  5. 748
  6. 396
  7. 1012
  8. 506
  9. 649
  10. 594
  11. 473
  12. 715
  13. 286
  14. 946
  15. 836
  16. 792
  17. 616
  18. 396
  19. 583
  20. 671
  21. 847
  22. 1199
  23. 814
  24. 572
  25. 319
  26. 792
  27. 891
  28. 759
  29. 198
  30. 880
  31. 979
  32. 924
  33. 594
  34. 803
  35. 1089
  36. 506
  37. 836
  38. 1023
  39. 143
  40. 143

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