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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 347 · 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. 2.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  3. 3.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?
  4. 4.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  5. 5.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  6. 6.A leapfrog list starts 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.8 + 6 + 14 + 20 + 34 + 54 + 88 + 142 + 230 + 372 =
  8. 8.A leapfrog list starts 9, 4 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 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.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?
  11. 11.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?
  12. 12.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 9, 5, 14, 19, 33, 52, 85, 137, 222, 359. What is 11 × the 7th number?
  14. 14.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  15. 15.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  16. 16.Leapfrog list (each number is the sum of the two before it): 6, 6, 12, 18, 30, 48, 78, 126, 204, 330. What is 11 × the 7th number?
  17. 17.Leapfrog list (each number is the sum of the two before it): 9, 4, 13, 17, 30, 47, 77, 124, 201, 325. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 5, 6 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): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  20. 20.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  21. 21.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  22. 22.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  23. 23.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?
  24. 24.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  25. 25.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  26. 26.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 3, 1, 4, 5, 9, 14, 23, 37, 60, 97. What is 11 × the 7th number?
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 5, 5, 10, 15, 25, 40, 65, 105, 170, 275. What is 11 × the 7th number?
  30. 30.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  31. 31.7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 + 453 =
  32. 32.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?
  33. 33.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?
  34. 34.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  35. 35.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 1, 9, 10, 19, 29, 48, 77, 125, 202, 327. What is 11 × the 7th number?
  37. 37.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?
  38. 38.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  39. 39.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  40. 40.A leapfrog list starts 2, 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. 1001
  3. 770
  4. 517
  5. 671
  6. 946
  7. 968
  8. 847
  9. 198
  10. 770
  11. 924
  12. 660
  13. 935
  14. 858
  15. 825
  16. 858
  17. 847
  18. 803
  19. 374
  20. 583
  21. 1012
  22. 737
  23. 913
  24. 583
  25. 748
  26. 869
  27. 253
  28. 594
  29. 715
  30. 594
  31. 1177
  32. 968
  33. 418
  34. 836
  35. 583
  36. 847
  37. 880
  38. 715
  39. 429
  40. 814

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