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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 776 · 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.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?
  2. 2.A leapfrog list starts 4, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 2, 6, 8, 14, 22, 36, 58, 94, 152. What is 11 × the 7th number?
  4. 4.A leapfrog list starts 2, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.A leapfrog list starts 7, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  6. 6.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?
  7. 7.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  8. 8.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  9. 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  10. 10.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?
  11. 11.A leapfrog list starts 8, 2 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  13. 13.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  14. 14.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  15. 15.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  16. 16.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?
  17. 17.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  18. 18.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  19. 19.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?
  20. 20.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?
  21. 21.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  22. 22.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  23. 23.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  24. 24.A leapfrog list starts 2, 4 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 7, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.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?
  27. 27.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  28. 28.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  29. 29.A leapfrog list starts 5, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  32. 32.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  33. 33.A leapfrog list starts 9, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  35. 35.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?
  36. 36.A leapfrog list starts 3, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  37. 37.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?
  38. 38.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?
  39. 39.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  40. 40.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?

Answer key

  1. 429
  2. 572
  3. 396
  4. 550
  5. 825
  6. 605
  7. 814
  8. 418
  9. 528
  10. 462
  11. 616
  12. 1089
  13. 847
  14. 583
  15. 638
  16. 143
  17. 517
  18. 682
  19. 759
  20. 1232
  21. 308
  22. 374
  23. 1023
  24. 462
  25. 737
  26. 946
  27. 550
  28. 1089
  29. 979
  30. 726
  31. 671
  32. 429
  33. 583
  34. 946
  35. 341
  36. 693
  37. 1012
  38. 286
  39. 231
  40. 1012

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