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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 456 · 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): 3, 2, 5, 7, 12, 19, 31, 50, 81, 131. What is 11 × the 7th number?
  2. 2.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?
  3. 3.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  4. 4.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?
  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 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  8. 8.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?
  9. 9.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  10. 10.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?
  11. 11.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  12. 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  14. 14.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?
  15. 15.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  18. 18.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?
  19. 19.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  20. 20.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  21. 21.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  22. 22.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 6, 5, 11, 16, 27, 43, 70, 113, 183, 296. What is 11 × the 7th number?
  28. 28.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  29. 29.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  30. 30.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  31. 31.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?
  32. 32.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?
  33. 33.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  36. 36.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  38. 38.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 341
  2. 671
  3. 748
  4. 1023
  5. 528
  6. 847
  7. 814
  8. 1089
  9. 737
  10. 957
  11. 484
  12. 660
  13. 957
  14. 627
  15. 1111
  16. 253
  17. 462
  18. 704
  19. 957
  20. 1012
  21. 671
  22. 825
  23. 231
  24. 198
  25. 605
  26. 341
  27. 770
  28. 759
  29. 1287
  30. 1144
  31. 1177
  32. 726
  33. 583
  34. 792
  35. 924
  36. 693
  37. 847
  38. 781
  39. 506
  40. 671

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