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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 716 · 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. 1.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  2. 2.8 + 1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 =
  3. 3.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?
  4. 4.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  5. 5.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?
  6. 6.A leapfrog list starts 8, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  8. 8.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  9. 9.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?
  10. 10.Leapfrog list (each number is the sum of the two before it): 2, 3, 5, 8, 13, 21, 34, 55, 89, 144. What is 11 × the 7th number?
  11. 11.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  12. 12.3 + 8 + 11 + 19 + 30 + 49 + 79 + 128 + 207 + 335 =
  13. 13.Leapfrog list (each number is the sum of the two before it): 3, 6, 9, 15, 24, 39, 63, 102, 165, 267. What is 11 × the 7th number?
  14. 14.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  15. 15.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?
  16. 16.3 + 2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 =
  17. 17.A leapfrog list starts 3, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  18. 18.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?
  19. 19.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?
  20. 20.9 + 7 + 16 + 23 + 39 + 62 + 101 + 163 + 264 + 427 =
  21. 21.4 + 3 + 7 + 10 + 17 + 27 + 44 + 71 + 115 + 186 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.9 + 9 + 18 + 27 + 45 + 72 + 117 + 189 + 306 + 495 =
  26. 26.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?
  27. 27.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?
  28. 28.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?
  29. 29.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?
  30. 30.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?
  31. 31.A leapfrog list starts 5, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  32. 32.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  33. 33.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  34. 34.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?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 3, 9, 12, 21, 33, 54, 87, 141, 228, 369. What is 11 × the 7th number?
  37. 37.Leapfrog list (each number is the sum of the two before it): 9, 7, 16, 23, 39, 62, 101, 163, 264, 427. What is 11 × the 7th number?
  38. 38.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?
  39. 39.A leapfrog list starts 5, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  40. 40.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?

Answer key

  1. 583
  2. 528
  3. 957
  4. 902
  5. 341
  6. 880
  7. 946
  8. 682
  9. 1287
  10. 374
  11. 253
  12. 869
  13. 693
  14. 363
  15. 198
  16. 341
  17. 781
  18. 495
  19. 231
  20. 1111
  21. 484
  22. 1232
  23. 528
  24. 946
  25. 1287
  26. 418
  27. 462
  28. 715
  29. 341
  30. 979
  31. 1067
  32. 286
  33. 407
  34. 396
  35. 759
  36. 957
  37. 1111
  38. 1287
  39. 803
  40. 638

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