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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 670 · 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 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 4, 8, 12, 20, 32, 52, 84, 136, 220. What is 11 × the 7th number?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  5. 5.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?
  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. 7.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  8. 8.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  9. 9.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  10. 10.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?
  11. 11.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  13. 13.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?
  14. 14.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?
  15. 15.A leapfrog list starts 3, 8 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 5, 6 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, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  19. 19.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  20. 20.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  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. 23.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  27. 27.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  29. 29.7 + 2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 =
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  32. 32.A leapfrog list starts 1, 2 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, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  36. 36.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  37. 37.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  38. 38.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  39. 39.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  40. 40.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?

Answer key

  1. 198
  2. 583
  3. 572
  4. 319
  5. 528
  6. 946
  7. 429
  8. 286
  9. 792
  10. 1023
  11. 693
  12. 957
  13. 913
  14. 1089
  15. 869
  16. 803
  17. 539
  18. 935
  19. 1089
  20. 627
  21. 341
  22. 671
  23. 231
  24. 253
  25. 737
  26. 495
  27. 671
  28. 880
  29. 561
  30. 671
  31. 627
  32. 231
  33. 704
  34. 858
  35. 605
  36. 1287
  37. 913
  38. 803
  39. 583
  40. 1177

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