If you were to add &"" to the {% received}*1 you will most likely see the identical result that is in the email. That being the case, using ({% received}*1)&"" should give you the result you're looking for.
@shalablake
Give this a try - change 'percent' to the name of the field that has your percent that you want to format.
CONCATENATE(ROUND(percent*100),"%")
Hi shalablake,
In terms of a formula, have you tried something like:
ROUNDUP({received} * 100, 0)
One of the images appears to show a field that already shows the rounding calculated, so I'm guessing this is not the problem. In terms of adding the calculated field to an email, are you sure that you have the new (rounded field) in the email builder? Make sure you have switched it for the original {% received}. There are no images showing your email automation, so this is just a guess.

Another thing you can look at is formatting the rounded field to an integer. Although I don't think you'll find this is required.

@shalablake
Give this a try - change 'percent' to the name of the field that has your percent that you want to format.
CONCATENATE(ROUND(percent*100),"%")
this worked! I was so close and then kept over thinking it and go so far off! Thank you!