Let's look at rounding 44 to the nearest 10. First put 44 on the number line, then add the closest multiples of ten. 40 and 50 are the closest multiples of ten to 44. 44 is 4 away from 40 and 6 ...

This number line shows how this works for decimals between 1.6 and 1.7. A place value chart can be really helpful when rounding decimals. They help you see the value of each digit within a number.