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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 183 · 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): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  7. 7.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  8. 8.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?
  9. 9.Leapfrog list (each number is the sum of the two before it): 5, 6, 11, 17, 28, 45, 73, 118, 191, 309. What is 11 × the 7th number?
  10. 10.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  11. 11.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  12. 12.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.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?
  14. 14.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  15. 15.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  17. 17.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?
  18. 18.A leapfrog list starts 9, 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 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  21. 21.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  23. 23.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?
  24. 24.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?
  25. 25.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  26. 26.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?
  27. 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  29. 29.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  31. 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  37. 37.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?
  38. 38.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?
  39. 39.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  40. 40.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 671
  2. 693
  3. 957
  4. 726
  5. 825
  6. 1067
  7. 858
  8. 649
  9. 803
  10. 1122
  11. 1144
  12. 1001
  13. 231
  14. 968
  15. 506
  16. 308
  17. 1287
  18. 671
  19. 550
  20. 363
  21. 517
  22. 1177
  23. 671
  24. 924
  25. 968
  26. 341
  27. 418
  28. 902
  29. 836
  30. 1199
  31. 660
  32. 946
  33. 726
  34. 913
  35. 231
  36. 924
  37. 891
  38. 198
  39. 946
  40. 979

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