Property
To estimate the quotient when dividing by a multiple of 10, use basic division facts. Think of the dividend and divisor in terms of tens.
For example, to solve 84÷20, you can think of it as 8 tens÷2 tens, which simplifies to 8÷2.
Examples
- To estimate 72÷30, think: How many 3s are in 7? The answer is 2. So, 72÷30≈2. (60÷30=2)
- To estimate 154÷50, think: How many 5s are in 15? The answer is 3. So, 154÷50≈3. (150÷50=3)
- To estimate 430÷60, think: How many 6s are in 43? The answer is 7. So, 430÷60≈7. (420÷60=7)
Explanation
Estimating helps you find an answer that is close to the exact quotient before you start long division. By using basic facts, you can simplify the problem and make a reasonable guess. This strategy is useful for determining the first digit of your quotient in the standard algorithm. It also helps you check if your final answer makes sense.