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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 986 · 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.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?
  2. 2.5 + 8 + 13 + 21 + 34 + 55 + 89 + 144 + 233 + 377 =
  3. 3.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  4. 4.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?
  5. 5.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?
  6. 6.A leapfrog list starts 9, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  7. 7.9 + 1 + 10 + 11 + 21 + 32 + 53 + 85 + 138 + 223 =
  8. 8.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  9. 9.A leapfrog list starts 6, 4 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 8, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  11. 11.4 + 2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 =
  12. 12.Leapfrog list (each number is the sum of the two before it): 4, 6, 10, 16, 26, 42, 68, 110, 178, 288. What is 11 × the 7th number?
  13. 13.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?
  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.Leapfrog list (each number is the sum of the two before it): 6, 2, 8, 10, 18, 28, 46, 74, 120, 194. What is 11 × the 7th number?
  16. 16.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  17. 17.1 + 9 + 10 + 19 + 29 + 48 + 77 + 125 + 202 + 327 =
  18. 18.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?
  19. 19.A leapfrog list starts 3, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  20. 20.A leapfrog list starts 3, 3 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  22. 22.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?
  23. 23.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?
  24. 24.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?
  25. 25.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?
  26. 26.6 + 4 + 10 + 14 + 24 + 38 + 62 + 100 + 162 + 262 =
  27. 27.Leapfrog list (each number is the sum of the two before it): 5, 9, 14, 23, 37, 60, 97, 157, 254, 411. What is 11 × the 7th number?
  28. 28.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  29. 29.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?
  30. 30.6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 + 432 =
  31. 31.4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 + 356 =
  32. 32.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?
  33. 33.3 + 3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 =
  34. 34.7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 + 259 + 419 =
  35. 35.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?
  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. 37.5 + 2 + 7 + 9 + 16 + 25 + 41 + 66 + 107 + 173 =
  38. 38.1 + 5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 =
  39. 39.5 + 6 + 11 + 17 + 28 + 45 + 73 + 118 + 191 + 309 =
  40. 40.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?

Answer key

  1. 1111
  2. 979
  3. 363
  4. 286
  5. 946
  6. 671
  7. 583
  8. 407
  9. 682
  10. 968
  11. 396
  12. 748
  13. 627
  14. 913
  15. 506
  16. 572
  17. 847
  18. 935
  19. 605
  20. 429
  21. 957
  22. 462
  23. 495
  24. 319
  25. 198
  26. 682
  27. 1067
  28. 550
  29. 550
  30. 1122
  31. 924
  32. 231
  33. 429
  34. 1089
  35. 363
  36. 825
  37. 451
  38. 495
  39. 803
  40. 1232

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