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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 987 · 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  2. 2.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?
  3. 3.A leapfrog list starts 9, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 9, 3, 12, 15, 27, 42, 69, 111, 180, 291. What is 11 × the 7th number?
  6. 6.2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 + 314 =
  7. 7.Leapfrog list (each number is the sum of the two before it): 4, 5, 9, 14, 23, 37, 60, 97, 157, 254. What is 11 × the 7th number?
  8. 8.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?
  9. 9.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  10. 10.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?
  11. 11.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?
  12. 12.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?
  13. 13.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?
  14. 14.A leapfrog list starts 8, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  16. 16.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?
  17. 17.4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 + 178 + 288 =
  18. 18.A leapfrog list starts 7, 9 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, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  20. 20.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?
  21. 21.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 =
  26. 26.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?
  27. 27.A leapfrog list starts 3, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.A leapfrog list starts 4, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  31. 31.A leapfrog list starts 4, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.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?
  33. 33.A leapfrog list starts 1, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  34. 34.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?
  35. 35.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  36. 36.Leapfrog list (each number is the sum of the two before it): 2, 6, 8, 14, 22, 36, 58, 94, 152, 246. What is 11 × the 7th number?
  37. 37.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?
  38. 38.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?
  39. 39.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  40. 40.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?

Answer key

  1. 1089
  2. 1232
  3. 1023
  4. 660
  5. 759
  6. 814
  7. 660
  8. 935
  9. 528
  10. 979
  11. 550
  12. 726
  13. 605
  14. 528
  15. 143
  16. 660
  17. 748
  18. 1177
  19. 814
  20. 143
  21. 341
  22. 495
  23. 814
  24. 1199
  25. 374
  26. 770
  27. 341
  28. 418
  29. 484
  30. 671
  31. 836
  32. 462
  33. 759
  34. 671
  35. 946
  36. 638
  37. 1056
  38. 715
  39. 495
  40. 924

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