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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 524 · 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. 1.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  2. 2.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  3. 3.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?
  4. 4.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?
  5. 5.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?
  6. 6.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  7. 7.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  8. 8.A leapfrog list starts 6, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  10. 10.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  12. 12.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  13. 13.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  15. 15.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  16. 16.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  17. 17.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.A leapfrog list starts 7, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  21. 21.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  24. 24.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  25. 25.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  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.A leapfrog list starts 4, 1 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): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  29. 29.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?
  30. 30.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?
  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.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  34. 34.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?
  35. 35.A leapfrog list starts 1, 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 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?

Answer key

  1. 1023
  2. 770
  3. 803
  4. 726
  5. 253
  6. 198
  7. 902
  8. 1122
  9. 1001
  10. 693
  11. 1056
  12. 396
  13. 550
  14. 781
  15. 913
  16. 1287
  17. 847
  18. 561
  19. 1232
  20. 1034
  21. 825
  22. 1177
  23. 660
  24. 528
  25. 616
  26. 495
  27. 308
  28. 1144
  29. 671
  30. 605
  31. 374
  32. 957
  33. 1232
  34. 759
  35. 495
  36. 407
  37. 319
  38. 517
  39. 462
  40. 638

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