answer: b
work:
let's solve by looking at the options.
<em>option one: </em>we can see right away that this is incorrect because it involves multiplication, and the first operation is multiplying 30 x 10. since the number is 30.425, only slightly more than 30, we know this isn't an option since 30 x 10 is 300, and the number only gets bigger from there.
<em>option two: </em>this option is correct. in standard form, thirty is 30, and four hundred twenty five thousandths is ".425", so putting those together you get 30.425
<em>options three and four: </em>we already know these are incorrect because b is the answer, but option three has adding 4 to 3 x 10, which results in 34, which is already larger than 30.425. lastly, the last one is also incorrect because it doesn't have thousandths at the end, which it needs, and doesn't make sense otherwise.
