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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 659 · 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. 1.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  2. 2.Leapfrog list (each number is the sum of the two before it): 7, 7, 14, 21, 35, 56, 91, 147, 238, 385. What is 11 × the 7th number?
  3. 3.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?
  4. 4.Leapfrog list (each number is the sum of the two before it): 1, 5, 6, 11, 17, 28, 45, 73, 118, 191. What is 11 × the 7th number?
  5. 5.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?
  6. 6.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?
  7. 7.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?
  8. 8.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?
  9. 9.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?
  10. 10.1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 1, 3, 4, 7, 11, 18, 29, 47, 76, 123. What is 11 × the 7th number?
  12. 12.A leapfrog list starts 9, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  13. 13.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  14. 14.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  15. 15.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  16. 16.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  17. 17.8 + 7 + 15 + 22 + 37 + 59 + 96 + 155 + 251 + 406 =
  18. 18.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  19. 19.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?
  20. 20.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  21. 21.7 + 5 + 12 + 17 + 29 + 46 + 75 + 121 + 196 + 317 =
  22. 22.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?
  23. 23.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?
  24. 24.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  25. 25.Leapfrog list (each number is the sum of the two before it): 5, 4, 9, 13, 22, 35, 57, 92, 149, 241. What is 11 × the 7th number?
  26. 26.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?
  27. 27.A leapfrog list starts 8, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  28. 28.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?
  29. 29.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?
  30. 30.A leapfrog list starts 1, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  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): 9, 2, 11, 13, 24, 37, 61, 98, 159, 257. What is 11 × the 7th number?
  36. 36.Leapfrog list (each number is the sum of the two before it): 4, 7, 11, 18, 29, 47, 76, 123, 199, 322. What is 11 × the 7th number?
  37. 37.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  38. 38.A leapfrog list starts 5, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  39. 39.3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 =
  40. 40.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?

Answer key

  1. 308
  2. 1001
  3. 143
  4. 495
  5. 539
  6. 1177
  7. 319
  8. 572
  9. 550
  10. 671
  11. 319
  12. 1199
  13. 869
  14. 759
  15. 792
  16. 583
  17. 1056
  18. 715
  19. 935
  20. 495
  21. 825
  22. 341
  23. 1199
  24. 671
  25. 627
  26. 748
  27. 704
  28. 770
  29. 671
  30. 231
  31. 660
  32. 957
  33. 1122
  34. 946
  35. 671
  36. 836
  37. 759
  38. 363
  39. 605
  40. 495

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