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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 142 · 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): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 4, 11, 15, 26, 41, 67, 108, 175, 283. What is 11 × the 7th number?
  3. 3.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  4. 4.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  5. 5.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?
  6. 6.A leapfrog list starts 6, 7 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): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  8. 8.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  9. 9.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  10. 10.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?
  11. 11.A leapfrog list starts 2, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  13. 13.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?
  14. 14.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  15. 15.A leapfrog list starts 6, 4 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): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  17. 17.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  18. 18.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  19. 19.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?
  20. 20.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?
  21. 21.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  22. 22.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.Leapfrog list (each number is the sum of the two before it): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  27. 27.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  28. 28.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  30. 30.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?
  31. 31.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  32. 32.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?
  33. 33.A leapfrog list starts 3, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  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. 36.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  37. 37.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  38. 38.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  39. 39.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?
  40. 40.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?

Answer key

  1. 968
  2. 737
  3. 583
  4. 572
  5. 693
  6. 946
  7. 935
  8. 1056
  9. 374
  10. 737
  11. 814
  12. 671
  13. 528
  14. 1199
  15. 682
  16. 638
  17. 649
  18. 253
  19. 704
  20. 407
  21. 495
  22. 979
  23. 770
  24. 814
  25. 462
  26. 550
  27. 583
  28. 803
  29. 396
  30. 803
  31. 594
  32. 1067
  33. 869
  34. 957
  35. 231
  36. 550
  37. 924
  38. 759
  39. 759
  40. 198

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