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Lesson 2: Estimation word problems

2-step estimation word problems

Sal solves a 2-step estimation word problem with whole numbers.

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• I didn't understood :( Why should we change the amount?
• because, the question asked to estimate. So sal rounded to the nearest tens place
• Total tires needed: 28 cars * 4 tires/car = 112 tires

Subtract the tires he already has: 112 needed tires - 22 existing tires = 90 tires to buy

So, the race car driver needs to buy approximately 90 tires.
• No one hundred 💯
• It’d two different answer how does this make sense
• What does estimate mean?
• To estimate means to make a good guess. It's like when you look at a jar of jellybeans and try to guess how many are inside. You don't count each one, but you make a good guess based on what you see. In math, we often estimate to make numbers easier to work with. For example, if a number is 28, we might estimate it to 30 because it's a "friendlier" number.
• When is it more useful to use estimation in real life?
• Estimation can be extremely useful in real life. Say grocery shopping, if you bought many goods worth different prices, it would be nice for you to maybe round the value up or down to get an idea of how much your items cost, the cashier may make a mistake, you never know!

Hope this helps!
• Can someone give me an example of PEMDAS ? Because I don't know it.╮(╯_╰)╭
• Here is an example off of https://www.onlinemathlearning.com/order-of-operations.html

Always work on the calculations within parenthesis first if any.
Next, calculate the exponents.
Then, carry out multiplication or division, working from left to right.
Lastly, do addition or subtraction, working from left to right.

``Example:Evaluate 10 ÷ 2 + 12 ÷ 2 × 3``

Solution:
Using the PEMDAS rule, we need to evaluate the division and multiplication before subtraction and addition. It is recommended that you put in parenthesis to remind yourself the order of operation.

``10 ÷ 2 + 12 ÷ 2 × 3= (10 ÷ 2) + (12 ÷ 2 × 3)= 5 + 18= 23``

Hope this helps!
(1 vote)
• the answer is 112 right
• and why do we have to estimate? I don't under stand:{
(1 vote)
• It's best to estimate when you want to have an idea of how much the number is going to be, before you actually calculate that number. Also, you can know when you made a mistake.
• hi what's 0+0 because
(1 vote)
• 0+0=0 cause if you add 0 to 0 it equals 0