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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 593 · 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 3, 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): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  3. 3.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?
  4. 4.6 + 5 + 11 + 16 + 27 + 43 + 70 + 113 + 183 + 296 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 6, 8, 14, 22, 36, 58, 94, 152, 246, 398. What is 11 × the 7th number?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 1, 1, 2, 3, 5, 8, 13, 21, 34, 55. What is 11 × the 7th number?
  9. 9.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  10. 10.A leapfrog list starts 6, 2 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 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.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?
  18. 18.A leapfrog list starts 5, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.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?
  20. 20.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  21. 21.A leapfrog list starts 2, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  25. 25.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  26. 26.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 5, 1, 6, 7, 13, 20, 33, 53, 86, 139. What is 11 × the 7th number?
  28. 28.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  29. 29.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  30. 30.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  31. 31.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  32. 32.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  33. 33.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  34. 34.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  35. 35.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.Leapfrog list (each number is the sum of the two before it): 2, 1, 3, 4, 7, 11, 18, 29, 47, 76. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.Leapfrog list (each number is the sum of the two before it): 3, 3, 6, 9, 15, 24, 39, 63, 102, 165. What is 11 × the 7th number?
  39. 39.Leapfrog list (each number is the sum of the two before it): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  40. 40.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =

Answer key

  1. 957
  2. 1023
  3. 902
  4. 770
  5. 649
  6. 1034
  7. 374
  8. 143
  9. 550
  10. 506
  11. 1067
  12. 682
  13. 781
  14. 231
  15. 913
  16. 1287
  17. 759
  18. 451
  19. 957
  20. 671
  21. 286
  22. 429
  23. 715
  24. 528
  25. 803
  26. 847
  27. 363
  28. 1144
  29. 1287
  30. 286
  31. 1034
  32. 935
  33. 726
  34. 594
  35. 253
  36. 198
  37. 759
  38. 429
  39. 594
  40. 616

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