can somebody do this math?

I think you mean $61.00 + 30% of $61.00
= $61.00 + 30/100 * $61.00
= $61.00 + 3 * $6.10
= $61.00 + $18.30
= $79.30

30% of 61$ is 18.3 (61*30/100). Total is 79.3

No I cannot. Unless you tell me 30% of what?

$61 + $61 x 30%
= $61 x (1 + 30%)
= $61 x 130%
= $61 x 130/100
= $61 x 13/10
= $793/10
= $79.3

$79.30