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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 675 · 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. 1.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  2. 2.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  3. 3.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  4. 4.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 8, 9, 17, 26, 43, 69, 112, 181, 293, 474. What is 11 × the 7th number?
  6. 6.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  7. 7.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?
  8. 8.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  9. 9.A leapfrog list starts 8, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.Leapfrog list (each number is the sum of the two before it): 3, 5, 8, 13, 21, 34, 55, 89, 144, 233. What is 11 × the 7th number?
  11. 11.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.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?
  17. 17.6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 + 398 =
  18. 18.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?
  19. 19.Leapfrog list (each number is the sum of the two before it): 6, 4, 10, 14, 24, 38, 62, 100, 162, 262. What is 11 × the 7th number?
  20. 20.Leapfrog list (each number is the sum of the two before it): 2, 2, 4, 6, 10, 16, 26, 42, 68, 110. What is 11 × the 7th number?
  21. 21.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  22. 22.A leapfrog list starts 4, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  24. 24.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  25. 25.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  26. 26.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  28. 28.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  29. 29.Leapfrog list (each number is the sum of the two before it): 7, 2, 9, 11, 20, 31, 51, 82, 133, 215. What is 11 × the 7th number?
  30. 30.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  31. 31.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?
  32. 32.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  33. 33.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?
  34. 34.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  35. 35.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  36. 36.A leapfrog list starts 4, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.5 + 4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 =
  38. 38.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.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?
  40. 40.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =

Answer key

  1. 836
  2. 869
  3. 143
  4. 1111
  5. 1232
  6. 781
  7. 198
  8. 198
  9. 792
  10. 605
  11. 1111
  12. 374
  13. 319
  14. 253
  15. 341
  16. 902
  17. 1034
  18. 671
  19. 682
  20. 286
  21. 946
  22. 660
  23. 495
  24. 759
  25. 902
  26. 1056
  27. 693
  28. 594
  29. 561
  30. 737
  31. 1023
  32. 1012
  33. 770
  34. 1089
  35. 935
  36. 924
  37. 627
  38. 605
  39. 891
  40. 1177

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