Estimating products by rounding numbers to the nearest ten, hundred, thousand etc., we know how to estimate the sum, difference, etc., to the nearest 10, 100, 1000, etc. Now we have to estimate the products.
In order to estimate products, we round the given factors to the
required place value. Estimating products help us to check the
reasonableness of an answer.
1. Estimate the products of 34 and 86.
34 ⟶ 30 34 is rounded down to 30
86 ⟶ 90 86 rounded up to 90
34 ⟶ 30 86 ⟶ 90 
34 is rounded down to 30 86 rounded up to 90 
Calculate mentally 30 × 90 = 2700
The estimated product is 2700.
2. Estimate the products of 331 and 267 by rounding to the nearest hundred.
331 ⟶ 300
267 ⟶ 300
300 × 300 = 90000
The estimated product is 90000.
Consider the following examples on estimating products:
1. Estimate the product: 42 × 57
Solution:
4 2 → 4 0
× 5 7 → × 6 0
2 4 0 0
Thus estimated product = 2400
2. Estimate the product: 47 × 84
Solution:
4 7 × 8 4 47 is rounded up to 50
↓ ↓
5 0 × 8 0 84 is rounded down to 80
= 4 0 0 0
The estimated product = 4000
3. Estimate the product: 74 × 85
Solution:
7 4 × 8 5 74 is rounded up to 80
↓ ↓
7 0 × 9 0 85 is rounded down to 90
= 6 3 0 0
6300 is the estimated product
4. Estimate the product: 358 × 326
Solution:
One number is rounded up and the other is rounded down. Here 358 is
rounded up to the nearest hundred, i.e., 400 while 326 is rounded down
to the nearest hundred, i.e., 300.
3 5 8 × 3 2 6 358 is rounded up to 400
↓ ↓
4 0 0 × 3 0 0 326 is rounded down to 300
= 1 2 0 0 0 0
120000 is the estimated product
5. Estimate the following product by rounding numbers to the nearest;
(i) Hundred
(ii) Ten ‘341 × 267’
Solution:
(i) 3 4 1 × 2 6 7 341 is rounded up to 300
↓ ↓
3 0 0 × 3 0 0 267 is rounded down to 300
= 90,000 & The estimated product is 90,000
(ii) 3 4 1 × 2 6 7 341 is rounded down to 340, the nearest ten
↓ ↓
3 4 0 × 2 7 0 267 is rounded up to 270, the nearest ten
= 91,800 The estimated product is 91,800
Related Concept
● Addition
● Check for Subtraction and Addition
● Word Problems Involving Addition and Subtraction
● Estimating Sums and Differences
● Multiply a Number by a 2Digit Number
● Multiplication of a Number by a 3Digit Number
● Word Problems on Multiplication
● Division of TwoDigit by a OneDigit Numbers
● Division of FourDigit by a OneDigit Numbers
● Division by 10 and 100 and 1000
● Division by TwoDigit Numbers
4th Grade Math Activities
From Estimating Products to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.

New! Comments
Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.