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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 888 · 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): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  2. 2.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  3. 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  4. 4.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?
  5. 5.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  7. 7.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  8. 8.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?
  9. 9.A leapfrog list starts 1, 3 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 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  12. 12.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  13. 13.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  14. 14.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  15. 15.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  18. 18.Leapfrog list (each number is the sum of the two before it): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  21. 21.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  23. 23.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  28. 28.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  29. 29.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  30. 30.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  33. 33.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  35. 35.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?
  36. 36.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  37. 37.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?
  38. 38.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  39. 39.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?
  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. 308
  2. 583
  3. 363
  4. 693
  5. 825
  6. 792
  7. 319
  8. 550
  9. 319
  10. 759
  11. 341
  12. 858
  13. 594
  14. 506
  15. 561
  16. 495
  17. 418
  18. 891
  19. 1199
  20. 407
  21. 253
  22. 803
  23. 429
  24. 770
  25. 869
  26. 605
  27. 781
  28. 308
  29. 682
  30. 1056
  31. 1232
  32. 1034
  33. 418
  34. 715
  35. 462
  36. 528
  37. 143
  38. 913
  39. 858
  40. 231

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