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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 678 · 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. 1.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  2. 2.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?
  3. 3.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?
  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.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  8. 8.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  9. 9.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  10. 10.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 4, 9, 13, 22, 35, 57, 92, 149, 241, 390. What is 11 × the 7th number?
  12. 12.7 + 6 + 13 + 19 + 32 + 51 + 83 + 134 + 217 + 351 =
  13. 13.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  14. 14.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?
  15. 15.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?
  16. 16.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  18. 18.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  19. 19.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?
  20. 20.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?
  21. 21.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  22. 22.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  23. 23.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  24. 24.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  25. 25.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  27. 27.A leapfrog list starts 8, 2 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 7, 3 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 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  31. 31.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  32. 32.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?
  33. 33.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  34. 34.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?
  35. 35.A leapfrog list starts 2, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  37. 37.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  38. 38.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  40. 40.A leapfrog list starts 2, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 1144
  2. 308
  3. 726
  4. 726
  5. 396
  6. 957
  7. 649
  8. 473
  9. 1012
  10. 308
  11. 1012
  12. 913
  13. 979
  14. 957
  15. 1122
  16. 858
  17. 737
  18. 869
  19. 1287
  20. 1199
  21. 924
  22. 462
  23. 583
  24. 484
  25. 341
  26. 451
  27. 616
  28. 649
  29. 781
  30. 539
  31. 759
  32. 737
  33. 759
  34. 561
  35. 462
  36. 957
  37. 649
  38. 319
  39. 319
  40. 374

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