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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 565 · 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, 1, 8, 9, 17, 26, 43, 69, 112, 181. What is 11 × the 7th number?
  2. 2.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  3. 3.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?
  4. 4.A leapfrog list starts 7, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  5. 5.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  6. 6.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?
  7. 7.A leapfrog list starts 7, 1 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 6, 9 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, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.6 + 6 + 12 + 18 + 30 + 48 + 78 + 126 + 204 + 330 =
  11. 11.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  12. 12.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  13. 13.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?
  14. 14.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  15. 15.A leapfrog list starts 8, 8 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.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?
  17. 17.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  18. 18.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  19. 19.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  20. 20.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?
  21. 21.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?
  22. 22.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?
  23. 23.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  24. 24.Leapfrog list (each number is the sum of the two before it): 1, 7, 8, 15, 23, 38, 61, 99, 160, 259. What is 11 × the 7th number?
  25. 25.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?
  26. 26.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?
  27. 27.1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 =
  28. 28.Leapfrog list (each number is the sum of the two before it): 8, 5, 13, 18, 31, 49, 80, 129, 209, 338. What is 11 × the 7th number?
  29. 29.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?
  30. 30.Leapfrog list (each number is the sum of the two before it): 8, 1, 9, 10, 19, 29, 48, 77, 125, 202. What is 11 × the 7th number?
  31. 31.8 + 5 + 13 + 18 + 31 + 49 + 80 + 129 + 209 + 338 =
  32. 32.Leapfrog list (each number is the sum of the two before it): 7, 9, 16, 25, 41, 66, 107, 173, 280, 453. What is 11 × the 7th number?
  33. 33.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?
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 7, 5, 12, 17, 29, 46, 75, 121, 196, 317. What is 11 × the 7th number?
  37. 37.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?
  38. 38.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  39. 39.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  40. 40.Leapfrog list (each number is the sum of the two before it): 6, 7, 13, 20, 33, 53, 86, 139, 225, 364. What is 11 × the 7th number?

Answer key

  1. 473
  2. 484
  3. 660
  4. 1089
  5. 682
  6. 528
  7. 473
  8. 1122
  9. 462
  10. 858
  11. 803
  12. 286
  13. 1199
  14. 407
  15. 1144
  16. 363
  17. 715
  18. 1287
  19. 638
  20. 319
  21. 1232
  22. 1287
  23. 495
  24. 671
  25. 957
  26. 231
  27. 319
  28. 880
  29. 836
  30. 528
  31. 880
  32. 1177
  33. 660
  34. 198
  35. 924
  36. 825
  37. 1001
  38. 660
  39. 616
  40. 946

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