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Leapfrog Sum Trick Worksheet

Maths tricks trick 25: The leapfrog sum trick · Set 521 · 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. 2.1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 + 293 =
  3. 3.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?
  4. 4.7 + 7 + 14 + 21 + 35 + 56 + 91 + 147 + 238 + 385 =
  5. 5.1 + 2 + 3 + 5 + 8 + 13 + 21 + 34 + 55 + 89 =
  6. 6.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?
  7. 7.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?
  8. 8.3 + 6 + 9 + 15 + 24 + 39 + 63 + 102 + 165 + 267 =
  9. 9.9 + 5 + 14 + 19 + 33 + 52 + 85 + 137 + 222 + 359 =
  10. 10.1 + 6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 =
  11. 11.A leapfrog list starts 2, 6 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  12. 12.2 + 9 + 11 + 20 + 31 + 51 + 82 + 133 + 215 + 348 =
  13. 13.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?
  14. 14.A leapfrog list starts 6, 3 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 2, 1 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): 2, 5, 7, 12, 19, 31, 50, 81, 131, 212. What is 11 × the 7th number?
  17. 17.4 + 4 + 8 + 12 + 20 + 32 + 52 + 84 + 136 + 220 =
  18. 18.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?
  19. 19.A leapfrog list starts 7, 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 1, 5 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  21. 21.Leapfrog list (each number is the sum of the two before it): 2, 8, 10, 18, 28, 46, 74, 120, 194, 314. What is 11 × the 7th number?
  22. 22.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?
  23. 23.7 + 4 + 11 + 15 + 26 + 41 + 67 + 108 + 175 + 283 =
  24. 24.A leapfrog list starts 9, 6 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): 7, 8, 15, 23, 38, 61, 99, 160, 259, 419. What is 11 × the 7th number?
  26. 26.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?
  27. 27.5 + 5 + 10 + 15 + 25 + 40 + 65 + 105 + 170 + 275 =
  28. 28.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?
  29. 29.Leapfrog list (each number is the sum of the two before it): 1, 8, 9, 17, 26, 43, 69, 112, 181, 293. What is 11 × the 7th number?
  30. 30.A leapfrog list starts 8, 2 and each next number is the sum of the two before it. What do the first 10 numbers add up to?
  31. 31.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?
  32. 32.3 + 9 + 12 + 21 + 33 + 54 + 87 + 141 + 228 + 369 =
  33. 33.2 + 2 + 4 + 6 + 10 + 16 + 26 + 42 + 68 + 110 =
  34. 34.6 + 7 + 13 + 20 + 33 + 53 + 86 + 139 + 225 + 364 =
  35. 35.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?
  36. 36.3 + 4 + 7 + 11 + 18 + 29 + 47 + 76 + 123 + 199 =
  37. 37.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?
  38. 38.3 + 1 + 4 + 5 + 9 + 14 + 23 + 37 + 60 + 97 =
  39. 39.7 + 1 + 8 + 9 + 17 + 26 + 43 + 69 + 112 + 181 =
  40. 40.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?

Answer key

  1. 583
  2. 759
  3. 462
  4. 1001
  5. 231
  6. 1287
  7. 561
  8. 693
  9. 935
  10. 583
  11. 638
  12. 902
  13. 627
  14. 594
  15. 198
  16. 550
  17. 572
  18. 649
  19. 825
  20. 495
  21. 814
  22. 341
  23. 737
  24. 1023
  25. 1089
  26. 583
  27. 715
  28. 979
  29. 759
  30. 616
  31. 462
  32. 957
  33. 286
  34. 946
  35. 660
  36. 517
  37. 231
  38. 253
  39. 473
  40. 726

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