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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 482 · 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): 7, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  3. 3.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?
  4. 4.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?
  5. 5.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  6. 6.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  7. 7.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?
  8. 8.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =
  9. 9.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  10. 10.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 4, 5, 9, 14, 23, 37, 60, 97, 157. What is 11 × the 7th number?
  12. 12.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  13. 13.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?
  14. 14.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?
  15. 15.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?
  16. 16.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  17. 17.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?
  18. 18.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  19. 19.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  20. 20.A leapfrog list starts 8, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  22. 22.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?
  23. 23.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  24. 24.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?
  25. 25.A leapfrog list starts 5, 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): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  27. 27.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  28. 28.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?
  29. 29.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  30. 30.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?
  31. 31.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 2, 4, 6, 10, 16, 26, 42, 68, 110, 178. What is 11 × the 7th number?
  33. 33.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  36. 36.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?
  37. 37.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  38. 38.2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 =
  39. 39.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 8, 2, 10, 12, 22, 34, 56, 90, 146, 236. What is 11 × the 7th number?

Answer key

  1. 957
  2. 913
  3. 231
  4. 682
  5. 671
  6. 627
  7. 671
  8. 1144
  9. 1001
  10. 1023
  11. 407
  12. 682
  13. 143
  14. 693
  15. 935
  16. 759
  17. 924
  18. 693
  19. 1111
  20. 1056
  21. 418
  22. 341
  23. 550
  24. 660
  25. 627
  26. 495
  27. 616
  28. 231
  29. 198
  30. 946
  31. 583
  32. 462
  33. 363
  34. 363
  35. 737
  36. 913
  37. 1287
  38. 462
  39. 528
  40. 616

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