691+221=
To solve this problem, we will add the mixed numbers 691 and 221 through the following steps:
Step 1: Convert each mixed number to an improper fraction.
- 691=955 because 6×9+1=55.
- 221=25 because 2×2+1=5.
Step 2: Find a common denominator for the fractions 955 and 25. The least common multiple of 9 and 2 is 18.
- Convert 955 to a denominator of 18: 955=18110.
- Convert 25 to a denominator of 18: 25=1845.
Step 3: Add the fractions together: 18110+1845=18155.
Step 4: Convert the improper fraction back to a mixed number.
- Divide 155 by 18 to get 8 with a remainder, 155÷18=8 remainder 11.
- Thus, the mixed number is 81811.
The solution to the problem is 81811, which corresponds to choice 3.
81811