21:4=
To solve this problem, we need to compute 21÷4. Here are the steps:
- Step 1: Recognize that dividing by 4 is equivalent to multiplying by its reciprocal, 41.
- Step 2: Rewrite the division as a multiplication: 21×41.
- Step 3: Perform the multiplication of fractions by multiplying their numerators and denominators. Thus, 2⋅41⋅1=81.
Therefore, the solution to the problem is 81.