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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 276 · 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  2. 2.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?
  3. 3.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?
  4. 4.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  5. 5.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?
  6. 6.Leapfrog list (each number is the sum of the two before it): 7, 3, 10, 13, 23, 36, 59, 95, 154, 249. What is 11 × the 7th number?
  7. 7.A leapfrog list starts 2, 2 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 8, 5 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 6, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  10. 10.A leapfrog list starts 1, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  12. 12.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?
  13. 13.Leapfrog list (each number is the sum of the two before it): 9, 6, 15, 21, 36, 57, 93, 150, 243, 393. What is 11 × the 7th number?
  14. 14.5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 + 411 =
  15. 15.A leapfrog list starts 5, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  16. 16.2 + 1 + 3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 =
  17. 17.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?
  18. 18.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  19. 19.4 + 1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 =
  20. 20.2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 + 280 =
  21. 21.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?
  22. 22.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  23. 23.A leapfrog list starts 2, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  24. 24.A leapfrog list starts 3, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  25. 25.Leapfrog list (each number is the sum of the two before it): 2, 9, 11, 20, 31, 51, 82, 133, 215, 348. What is 11 × the 7th number?
  26. 26.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  27. 27.4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 + 254 =
  28. 28.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?
  29. 29.6 + 2 + 8 + 10 + 18 + 28 + 46 + 74 + 120 + 194 =
  30. 30.4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 + 322 =
  31. 31.Leapfrog list (each number is the sum of the two before it): 8, 8, 16, 24, 40, 64, 104, 168, 272, 440. What is 11 × the 7th number?
  32. 32.8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 + 474 =
  33. 33.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  34. 34.8 + 2 + 10 + 12 + 22 + 34 + 56 + 90 + 146 + 236 =
  35. 35.A leapfrog list starts 5, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  36. 36.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  37. 37.5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 + 343 =
  38. 38.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?
  39. 39.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?
  40. 40.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?

Answer key

  1. 550
  2. 836
  3. 649
  4. 1023
  5. 528
  6. 649
  7. 286
  8. 880
  9. 946
  10. 407
  11. 418
  12. 231
  13. 1023
  14. 1067
  15. 715
  16. 198
  17. 660
  18. 1089
  19. 308
  20. 726
  21. 814
  22. 517
  23. 198
  24. 253
  25. 902
  26. 935
  27. 660
  28. 473
  29. 506
  30. 836
  31. 1144
  32. 1232
  33. 957
  34. 616
  35. 627
  36. 143
  37. 891
  38. 748
  39. 627
  40. 660

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