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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 969 · 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.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?
  2. 2.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?
  3. 3.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  4. 4.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  5. 5.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?
  6. 6.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  7. 7.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  8. 8.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?
  9. 9.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?
  10. 10.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  11. 11.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?
  12. 12.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  13. 13.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  14. 14.5 + 3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 =
  15. 15.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?
  16. 16.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?
  17. 17.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  18. 18.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  19. 19.A leapfrog list starts 9, 6 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 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.A leapfrog list starts 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  24. 24.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  26. 26.A leapfrog list starts 1, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  27. 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  28. 28.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?
  29. 29.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  30. 30.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?
  31. 31.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  32. 32.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  33. 33.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  34. 34.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?
  35. 35.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?
  36. 36.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  37. 37.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?
  38. 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  39. 39.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 902
  2. 968
  3. 374
  4. 869
  5. 957
  6. 583
  7. 1111
  8. 693
  9. 495
  10. 847
  11. 308
  12. 1067
  13. 748
  14. 539
  15. 957
  16. 231
  17. 792
  18. 1287
  19. 1023
  20. 880
  21. 770
  22. 484
  23. 418
  24. 1023
  25. 913
  26. 847
  27. 550
  28. 407
  29. 429
  30. 1012
  31. 616
  32. 253
  33. 726
  34. 825
  35. 374
  36. 583
  37. 616
  38. 462
  39. 429
  40. 1067

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