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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 122 · 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. 1.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  2. 2.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  3. 3.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?
  4. 4.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  5. 5.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  7. 7.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  8. 8.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?
  9. 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  10. 10.A leapfrog list starts 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  12. 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  13. 13.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  14. 14.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?
  15. 15.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  18. 18.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?
  19. 19.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?
  20. 20.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?
  21. 21.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  22. 22.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  24. 24.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?
  25. 25.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  32. 32.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  33. 33.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  35. 35.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?
  36. 36.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  37. 37.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  38. 38.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?
  39. 39.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  40. 40.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?

Answer key

  1. 715
  2. 814
  3. 561
  4. 583
  5. 363
  6. 462
  7. 550
  8. 418
  9. 374
  10. 737
  11. 1111
  12. 902
  13. 407
  14. 308
  15. 770
  16. 726
  17. 550
  18. 891
  19. 1232
  20. 539
  21. 605
  22. 253
  23. 847
  24. 957
  25. 1089
  26. 715
  27. 462
  28. 1177
  29. 1067
  30. 880
  31. 1144
  32. 341
  33. 1144
  34. 561
  35. 979
  36. 517
  37. 396
  38. 528
  39. 671
  40. 946

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