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## Class 7 (Foundation)

### Course: Class 7 (Foundation)>Unit 1

Lesson 2: Estimation problems

# Multiplication estimation example

Estimating the product of two, 2-digit numbers. Created by Sal Khan.

## Want to join the conversation?

• what is kilometers?
• Kilo means a thousand, therefore a kilometer is 1000 meters.
• math is to hard but khan makes it easier
• at what is rounding?
• Rounding is a type of estimating. 42 is close to 40 = 4 tens. 29 is close to 30 = 3 tens.
4 * 3 = 12 and 'tens place' times 'tens place' = 'hundreds place'
So our estimate is 12 hundred = 1200
• SO i get it a little bit but do you always multiply if so it would be a lot easier and also why do you round. PLEASE ANSWER I'm stuck
• no not always. it depends on what you need to find out, and as far as rounding goes, it's just a way to estimate (guess) when you don't need an exact anwser.
• Couldn't you just round the answer after you got the exact answer?
• You could but the idea is that with rounding the problem become much easier and you may find you can do it in your head.

Sometime we don't always need an exact answer but a good idea, this is why we use rounding.
• What is the point of estimating if its not even the right answer? even if its close, one little mistake will change the whole answer. Do they do it because it is faster?
• when u are rounding something to the nearest dollar estimating can be useful
• Math makes your brain think.