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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 578 · 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 6, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.9 + 4 + 13 + 17 + 30 + 47 + 77 + 124 + 201 + 325 =
  3. 3.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?
  4. 4.A leapfrog list starts 3, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  6. 6.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?
  7. 7.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?
  8. 8.Leapfrog list (each number is the sum of the two before it): 8, 3, 11, 14, 25, 39, 64, 103, 167, 270. What is 11 × the 7th number?
  9. 9.Leapfrog list (each number is the sum of the two before it): 5, 3, 8, 11, 19, 30, 49, 79, 128, 207. What is 11 × the 7th number?
  10. 10.Leapfrog list (each number is the sum of the two before it): 7, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  11. 11.A leapfrog list starts 4, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.Leapfrog list (each number is the sum of the two before it): 3, 8, 11, 19, 30, 49, 79, 128, 207, 335. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 8, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  16. 16.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?
  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 7, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  20. 20.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?
  21. 21.A leapfrog list starts 1, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.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?
  23. 23.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  24. 24.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?
  25. 25.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  26. 26.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?
  27. 27.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  28. 28.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  29. 29.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  30. 30.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?
  31. 31.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  32. 32.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  33. 33.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  34. 34.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?
  35. 35.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  36. 36.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?
  37. 37.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?
  38. 38.Leapfrog list (each number is the sum of the two before it): 9, 8, 17, 25, 42, 67, 109, 176, 285, 461. What is 11 × the 7th number?
  39. 39.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  40. 40.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?

Answer key

  1. 770
  2. 847
  3. 231
  4. 517
  5. 671
  6. 198
  7. 1287
  8. 704
  9. 539
  10. 473
  11. 1012
  12. 869
  13. 308
  14. 1232
  15. 1001
  16. 847
  17. 759
  18. 649
  19. 528
  20. 198
  21. 143
  22. 363
  23. 726
  24. 715
  25. 319
  26. 1067
  27. 715
  28. 803
  29. 979
  30. 726
  31. 429
  32. 1056
  33. 583
  34. 957
  35. 693
  36. 1056
  37. 429
  38. 1199
  39. 231
  40. 693

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