Add and Subtract Tens

Let's find the sum of 68 and 70.

68 + 70 = ?
 

Here,

68 can be written as 6 tens and 8 ones.

70 can be written as 7 tens.
 

So,

68 + 70 = 6 tens + 8 ones + 7 tens

 

Now, add tens.
 

6 tens + 8 ones + 7 tens

= (6 tens + 7 tens) + 8 ones

= 13 tens + 8 ones

= 138
 

So, 68 + 70 = 138.
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Help

The correct answer is

Remember :

The smallest number is the one that comes first while counting.

Solution :

To arrange the given numbers in order from smallest to greatest, find the smallest number among all the given numbers.

21,27,23

21 is the smallest number.