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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 545 · 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 7, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  2. 2.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?
  3. 3.Leapfrog list (each number is the sum of the two before it): 4, 3, 7, 10, 17, 27, 44, 71, 115, 186. What is 11 × the 7th number?
  4. 4.6 + 1 + 7 + 8 + 15 + 23 + 38 + 61 + 99 + 160 =
  5. 5.A leapfrog list starts 8, 7 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, 6, 13, 19, 32, 51, 83, 134, 217, 351. What is 11 × the 7th number?
  7. 7.5 + 1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 =
  8. 8.A leapfrog list starts 2, 9 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  9. 9.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  10. 10.1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 + 157 =
  11. 11.Leapfrog list (each number is the sum of the two before it): 3, 7, 10, 17, 27, 44, 71, 115, 186, 301. What is 11 × the 7th number?
  12. 12.Leapfrog list (each number is the sum of the two before it): 8, 6, 14, 20, 34, 54, 88, 142, 230, 372. What is 11 × the 7th number?
  13. 13.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?
  14. 14.A leapfrog list starts 4, 1 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  15. 15.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?
  16. 16.2 + 6 + 8 + 14 + 22 + 36 + 58 + 94 + 152 + 246 =
  17. 17.Leapfrog list (each number is the sum of the two before it): 1, 6, 7, 13, 20, 33, 53, 86, 139, 225. What is 11 × the 7th number?
  18. 18.A leapfrog list starts 9, 4 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  19. 19.Leapfrog list (each number is the sum of the two before it): 5, 8, 13, 21, 34, 55, 89, 144, 233, 377. What is 11 × the 7th number?
  20. 20.1 + 1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 =
  21. 21.9 + 6 + 15 + 21 + 36 + 57 + 93 + 150 + 243 + 393 =
  22. 22.A leapfrog list starts 2, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  23. 23.Leapfrog list (each number is the sum of the two before it): 6, 9, 15, 24, 39, 63, 102, 165, 267, 432. What is 11 × the 7th number?
  24. 24.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?
  25. 25.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?
  26. 26.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  27. 27.9 + 2 + 11 + 13 + 24 + 37 + 61 + 98 + 159 + 257 =
  28. 28.A leapfrog list starts 7, 2 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 6, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  30. 30.8 + 4 + 12 + 16 + 28 + 44 + 72 + 116 + 188 + 304 =
  31. 31.7 + 3 + 10 + 13 + 23 + 36 + 59 + 95 + 154 + 249 =
  32. 32.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?
  33. 33.4 + 9 + 13 + 22 + 35 + 57 + 92 + 149 + 241 + 390 =
  34. 34.A leapfrog list starts 5, 7 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  35. 35.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?
  36. 36.Leapfrog list (each number is the sum of the two before it): 9, 1, 10, 11, 21, 32, 53, 85, 138, 223. What is 11 × the 7th number?
  37. 37.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  38. 38.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  39. 39.2 + 5 + 7 + 12 + 19 + 31 + 50 + 81 + 131 + 212 =
  40. 40.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?

Answer key

  1. 913
  2. 572
  3. 484
  4. 418
  5. 1056
  6. 913
  7. 363
  8. 902
  9. 1001
  10. 407
  11. 781
  12. 968
  13. 231
  14. 308
  15. 924
  16. 638
  17. 583
  18. 847
  19. 979
  20. 143
  21. 1023
  22. 726
  23. 1122
  24. 715
  25. 671
  26. 902
  27. 671
  28. 561
  29. 506
  30. 792
  31. 649
  32. 957
  33. 1012
  34. 891
  35. 957
  36. 583
  37. 759
  38. 715
  39. 550
  40. 1287

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