First you explain what the dividend, the divisor, and the approximately equals sign are. Then you tell the students that with estimated division you always look for a dividend that is divisible by the divisor. Next you show estimation step by step. Explain that you first think of which numbers are divisible by the divisor. Find the outcome that is the closest to the dividend. After that you can solve the problem. Explain that you need to stay as close as possible to the dividend. This way, you will be closer to the exact answer. After this the students practice choosing the correct estimated quotient. Also explain why certain estimated division problems are not possible, because they will not give a whole number (for example, you can't round 68.911 ÷ 6 to 70 ÷ 6, but you can round it is 66 ÷ 6). Next the students are going to estimate quotients on their own. For this, explain that sometimes you also need to round the divisor, if it is also a decimal number. For this, start by looking for a good estimated division problem. Show this step by step. After that, have the students estimate division problems on their own, and ask how they rounded. Next discuss whether the exact answers are more or less than the estimate. Have the students reason how you can know this. Then recall the meaning of the symbols < and >.
Check whether the students can estimate quotients by asking them the following question:
- What do you do with the decimal number if you want to estimate a quotient?