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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 273 · 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. 1.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  2. 2.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.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?
  7. 7.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  8. 8.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  10. 10.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?
  11. 11.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 3, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.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?
  18. 18.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?
  19. 19.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?
  20. 20.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  21. 21.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  24. 24.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?
  25. 25.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  26. 26.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?
  27. 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  36. 36.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  38. 38.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?
  39. 39.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?

Answer key

  1. 814
  2. 1067
  3. 836
  4. 803
  5. 198
  6. 946
  7. 143
  8. 858
  9. 671
  10. 253
  11. 627
  12. 550
  13. 1023
  14. 957
  15. 1012
  16. 231
  17. 671
  18. 539
  19. 363
  20. 286
  21. 792
  22. 418
  23. 946
  24. 429
  25. 913
  26. 825
  27. 319
  28. 627
  29. 1012
  30. 693
  31. 649
  32. 836
  33. 847
  34. 484
  35. 759
  36. 924
  37. 1056
  38. 539
  39. 847
  40. 583

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