Answer
3.4 in words is: Three and four tenths
3.4 in expanded form 3+4/10
Explanation
Decimal points are fractions whose denominator is 10 or a power of 10. To write a decimal point in words we must be able to identify the place value of every digit.
3.4
3 is a whole number and its place value is ones and the place value of 4 is tenth.
So, 3.4 in words is: Three and four tenths
3.4 in expanded form 3+4/10