Solve the following exercise:
21−72=?
To solve the given problem 21−72, we need to follow these steps:
- Step 1: Find a common denominator for the fractions. The denominators are 2 and 7. The common denominator can be found by multiplying these two numbers: 2×7=14.
- Step 2: Convert the fractions to equivalent fractions with the common denominator. For 21, multiply the numerator and the denominator by 7:
21=2×71×7=147. For 72, multiply the numerator and the denominator by 2:
72=7×22×2=144.
- Step 3: Subtract the fractions. With a common denominator, subtract the numerators:
147−144=147−4=143.
- Step 4: Simplify the resulting fraction if needed. The fraction 143 is already in its simplest form.
Thus, the solution to the problem is 143.