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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 853 · 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 1, 7 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): 6, 1, 7, 8, 15, 23, 38, 61, 99, 160. What is 11 × the 7th number?
  3. 3.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?
  4. 4.A leapfrog list starts 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  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.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?
  9. 9.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  10. 10.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?
  11. 11.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  12. 12.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?
  13. 13.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?
  14. 14.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?
  15. 15.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.A leapfrog list starts 6, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.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?
  18. 18.Leapfrog list (each number is the sum of the two before it): 2, 7, 9, 16, 25, 41, 66, 107, 173, 280. What is 11 × the 7th number?
  19. 19.A leapfrog list starts 6, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.9 + 8 + 17 + 25 + 42 + 67 + 109 + 176 + 285 + 461 =
  21. 21.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  22. 22.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?
  23. 23.Leapfrog list (each number is the sum of the two before it): 4, 1, 5, 6, 11, 17, 28, 45, 73, 118. What is 11 × the 7th number?
  24. 24.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 8, 7, 15, 22, 37, 59, 96, 155, 251, 406. What is 11 × the 7th number?
  26. 26.9 + 3 + 12 + 15 + 27 + 42 + 69 + 111 + 180 + 291 =
  27. 27.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  28. 28.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?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  31. 31.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  32. 32.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  33. 33.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  34. 34.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?
  35. 35.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  37. 37.A leapfrog list starts 6, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  38. 38.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?
  39. 39.3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 + 301 =
  40. 40.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?

Answer key

  1. 671
  2. 418
  3. 913
  4. 968
  5. 506
  6. 583
  7. 1111
  8. 891
  9. 1122
  10. 1023
  11. 374
  12. 198
  13. 649
  14. 462
  15. 638
  16. 858
  17. 363
  18. 726
  19. 418
  20. 1199
  21. 836
  22. 1012
  23. 308
  24. 319
  25. 1056
  26. 759
  27. 418
  28. 495
  29. 1056
  30. 671
  31. 715
  32. 1067
  33. 759
  34. 286
  35. 869
  36. 748
  37. 1034
  38. 792
  39. 781
  40. 1199

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