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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 106 · 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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  2. 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  7. 7.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.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?
  9. 9.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  10. 10.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  11. 11.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  13. 13.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  14. 14.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?
  15. 15.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?
  16. 16.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  17. 17.A leapfrog list starts 9, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  19. 19.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  20. 20.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  21. 21.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  22. 22.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?
  23. 23.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  27. 27.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  28. 28.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  29. 29.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?
  30. 30.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?
  31. 31.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?
  32. 32.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?
  33. 33.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?
  34. 34.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?
  35. 35.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  36. 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  37. 37.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?
  38. 38.A leapfrog list starts 7, 6 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): 5, 7, 12, 19, 31, 50, 81, 131, 212, 343. What is 11 × the 7th number?
  40. 40.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =

Answer key

  1. 671
  2. 770
  3. 649
  4. 198
  5. 231
  6. 1012
  7. 572
  8. 671
  9. 792
  10. 979
  11. 1111
  12. 869
  13. 660
  14. 682
  15. 1199
  16. 231
  17. 1287
  18. 649
  19. 715
  20. 1067
  21. 935
  22. 836
  23. 451
  24. 143
  25. 836
  26. 1177
  27. 726
  28. 407
  29. 858
  30. 1144
  31. 374
  32. 418
  33. 1056
  34. 1177
  35. 473
  36. 583
  37. 396
  38. 913
  39. 891
  40. 671

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