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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 511 · 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.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  9. 9.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  10. 10.A leapfrog list starts 7, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  12. 12.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?
  13. 13.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  14. 14.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  15. 15.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  16. 16.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  17. 17.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?
  18. 18.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  19. 19.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?
  20. 20.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  21. 21.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?
  22. 22.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  23. 23.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  25. 25.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  26. 26.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?
  27. 27.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?
  28. 28.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  29. 29.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?
  30. 30.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  31. 31.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?
  32. 32.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?
  33. 33.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  34. 34.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  35. 35.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?
  36. 36.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  40. 40.A leapfrog list starts 1, 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. 858
  2. 407
  3. 616
  4. 825
  5. 286
  6. 759
  7. 539
  8. 1089
  9. 231
  10. 1177
  11. 198
  12. 1001
  13. 561
  14. 473
  15. 286
  16. 1144
  17. 528
  18. 506
  19. 528
  20. 957
  21. 891
  22. 1177
  23. 704
  24. 341
  25. 781
  26. 407
  27. 1122
  28. 671
  29. 473
  30. 649
  31. 594
  32. 759
  33. 1001
  34. 660
  35. 968
  36. 429
  37. 1023
  38. 1122
  39. 682
  40. 231

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