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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 752 · 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, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.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?
  5. 5.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  6. 6.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  13. 13.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.8 + 3 + 11 + 14 + 25 + 39 + 64 + 103 + 167 + 270 =
  15. 15.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  16. 16.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?
  17. 17.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?
  18. 18.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  19. 19.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  20. 20.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  22. 22.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.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?
  25. 25.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  26. 26.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  27. 27.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  33. 33.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  34. 34.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?
  35. 35.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?
  36. 36.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?
  37. 37.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?
  38. 38.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  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, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1232
  2. 407
  3. 253
  4. 550
  5. 781
  6. 1122
  7. 682
  8. 891
  9. 429
  10. 792
  11. 759
  12. 671
  13. 638
  14. 704
  15. 1199
  16. 594
  17. 363
  18. 594
  19. 341
  20. 1012
  21. 649
  22. 627
  23. 308
  24. 946
  25. 583
  26. 286
  27. 583
  28. 847
  29. 418
  30. 473
  31. 1001
  32. 550
  33. 814
  34. 1012
  35. 231
  36. 759
  37. 616
  38. 781
  39. 143
  40. 759

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