Estimate Differences

Consider the following options:

68 – 32

49 – 25

Let's identify the expression that has a difference nearly about 40.

Find the difference of each expression by rounding the numbers.
 

Let’s look at first option.
 

Round the numbers and then subtract.

 

68	–	32	=	?
↓		↓
70	–	30	=	40

The given expression has a difference of about 40.
 

Now, look at second option.

 

49	–	25	=	?
↓		↓
50	–	30	=	20

The given expression has a difference of about 20.

So, 68 – 32 has a difference nearly to 40.