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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 330 · 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, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  2. 2.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  3. 3.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  4. 4.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  5. 5.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  6. 6.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.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?
  8. 8.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  10. 10.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  14. 14.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  16. 16.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  17. 17.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  18. 18.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  20. 20.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  21. 21.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.A leapfrog list starts 1, 7 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, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  25. 25.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  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.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.Leapfrog list (each number is the sum of the two before it): 3, 4, 7, 11, 18, 29, 47, 76, 123, 199. What is 11 × the 7th number?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  31. 31.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  32. 32.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  34. 34.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  35. 35.A leapfrog list starts 4, 5 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 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  38. 38.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 506
  2. 1034
  3. 407
  4. 429
  5. 627
  6. 451
  7. 198
  8. 561
  9. 253
  10. 803
  11. 902
  12. 143
  13. 935
  14. 396
  15. 253
  16. 374
  17. 737
  18. 1089
  19. 1001
  20. 682
  21. 286
  22. 671
  23. 836
  24. 374
  25. 935
  26. 407
  27. 1001
  28. 517
  29. 891
  30. 561
  31. 462
  32. 1023
  33. 902
  34. 484
  35. 660
  36. 946
  37. 528
  38. 198
  39. 836
  40. 462

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