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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 607 · 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): 6, 3, 9, 12, 21, 33, 54, 87, 141, 228. What is 11 × the 7th number?
  2. 2.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  3. 3.A leapfrog list starts 7, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  4. 4.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  5. 5.Leapfrog list (each number is the sum of the two before it): 4, 8, 12, 20, 32, 52, 84, 136, 220, 356. What is 11 × the 7th number?
  6. 6.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  7. 7.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  8. 8.A leapfrog list starts 4, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  10. 10.A leapfrog list starts 1, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.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?
  12. 12.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?
  13. 13.A leapfrog list starts 9, 9 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  16. 16.A leapfrog list starts 9, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  17. 17.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  18. 18.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?
  19. 19.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?
  20. 20.A leapfrog list starts 9, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  22. 22.A leapfrog list starts 6, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.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?
  24. 24.6 + 3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 =
  25. 25.A leapfrog list starts 1, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  26. 26.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  27. 27.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?
  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. 29.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  30. 30.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  31. 31.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?
  32. 32.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  33. 33.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  34. 34.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?
  35. 35.A leapfrog list starts 4, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.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?
  37. 37.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  38. 38.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?
  39. 39.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  40. 40.8 + 8 + 16 + 24 + 40 + 64 + 104 + 168 + 272 + 440 =

Answer key

  1. 594
  2. 671
  3. 1001
  4. 1067
  5. 924
  6. 528
  7. 957
  8. 396
  9. 286
  10. 319
  11. 462
  12. 1034
  13. 1287
  14. 913
  15. 1089
  16. 1111
  17. 418
  18. 495
  19. 1089
  20. 935
  21. 825
  22. 594
  23. 704
  24. 594
  25. 583
  26. 1023
  27. 836
  28. 418
  29. 726
  30. 583
  31. 759
  32. 143
  33. 1056
  34. 968
  35. 748
  36. 1056
  37. 1287
  38. 649
  39. 583
  40. 1144

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