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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 807 · 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, 9, 18, 27, 45, 72, 117, 189, 306, 495. What is 11 × the 7th number?
  2. 2.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  3. 3.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  6. 6.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?
  7. 7.A leapfrog list starts 7, 5 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): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  9. 9.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?
  10. 10.A leapfrog list starts 9, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  13. 13.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  14. 14.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?
  15. 15.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?
  16. 16.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  17. 17.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?
  18. 18.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?
  19. 19.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.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?
  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. 22.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  25. 25.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  26. 26.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  27. 27.A leapfrog list starts 2, 6 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 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  29. 29.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?
  30. 30.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?
  31. 31.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  32. 32.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?
  33. 33.A leapfrog list starts 7, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  35. 35.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  37. 37.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  38. 38.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?
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =

Answer key

  1. 1287
  2. 1089
  3. 594
  4. 550
  5. 550
  6. 561
  7. 825
  8. 748
  9. 1023
  10. 759
  11. 1199
  12. 528
  13. 418
  14. 528
  15. 726
  16. 825
  17. 1111
  18. 836
  19. 748
  20. 253
  21. 341
  22. 759
  23. 616
  24. 429
  25. 759
  26. 957
  27. 638
  28. 231
  29. 198
  30. 374
  31. 693
  32. 682
  33. 473
  34. 1177
  35. 1012
  36. 847
  37. 198
  38. 660
  39. 616
  40. 429

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