Estimate Sums

Consider the following options:

48 + 47

12 + 49

74 + 24

28 + 51

Let's identify the expression that has a sum nearly about 80.

Find the sum of each expression by rounding the addends.
 

Let’s look at first option.
 

Round the addends to the nearest tens and then add.

 

48	+	47	=	?
↓		↓
50	+	50	=	100

 

This expression has a sum nearly equal to 100.
 

Now, look at second option.
 

12	+	49	=	?
↓		↓
10	+	50	=	60

This expression has a sum nearly equal to 60.
 

Now, look at third option.
 

74	+	24	=	?
↓		↓
70	+	20	=	90

This expression has a sum nearly equal to 90.
 

Now let’s look at the last option.
 

28	+	51	=	?
↓		↓
30	+	50	=	80

This expression has a sum nearly equal to 80.
 

So, 28 + 51 has a sum nearly to 80.