ESTIMATE

Estimate

Definition Of Estimate

To estimate is to find a number that is close to the exact answer.

Example of Estimate

A pen costs $4.15. Estimate the cost of 5 such pens.
$4.15 is closer to $4 than $5. So, the cost of 5 such pens would be about $20.

Video Examples: Estimating Sums and Differences

Solved Example on Estimate

Ques: Tim and his wife together earn $9,635 and spend $4,385 every month. Estimate the amount of money they save every month to the nearest thousand.

Choices:

A. $4,000
B. $14,000
C. $5,000
D. $6,000
Correct Answer: D

Solution:

Step 1: Tim and his wife together earn $9,635 and spend $4,385 every month.
Step 2: $9,635 rounded to the nearest thousand is $10,000.
Step 3: $4,385 rounded to the nearest thousand is $4,000.
Step 4: The amount they save every month
= 10,000 - 4,000 = 6,000.
Step 5: So, Tim and his wife save about $6,000 every month.

Real-world Connections for Estimate

Many companies use estimating techniques to find out the cost of buying materials or machineries, the cost involved in manufacturing goods, etc. The process of estimation gives them a fair idea of the amount to be invested.

Quick Summary

Estimation involves finding approximate values instead of exact answers.
Rounding is a key technique used in estimation.
Estimation is useful in real-world situations for quick calculations and checks.

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🍎 Teacher Insights

Encourage students to explain their reasoning when estimating. Provide real-world scenarios where estimation is useful, such as budgeting or grocery shopping. Use visual aids and manipulatives to demonstrate rounding concepts.

🎓 Prerequisites

Basic arithmetic operations (addition, subtraction, multiplication)
Rounding numbers to the nearest ten, hundred, or thousand

Check Your Knowledge

Q1: Estimate the sum of 28 + 42.

A. 60 B. 70 C. 80 D. 90

Q2: A book costs $9.85. Estimate the cost of 3 books.

A. $27 B. $28 C. $29 D. $30

Frequently Asked Questions

Q: Why do we need to estimate?
A: Estimation helps us quickly approximate answers when exact calculations are not necessary, or to check the reasonableness of an answer.

Q: How do I choose what place value to round to?
A: Choose a place value that makes the calculation easy while still providing a reasonably accurate estimate. The context of the problem often suggests an appropriate level of rounding.