Help with Conditional Tags

Hello,

I am looking to add a conditional tag so that Ads only show up on my blog page (which is a static page) and on all my blog posts. I do not want the ad showing up on any of my pages.

This is code I have so far using GSH
<?php if(is_page(100) || in_category( array( 37, 38, 39, 40, 42, 43, 44, 46, 48, 49, 50 ) ) { ?>
<?php } ?>

But I can’t seem to get it working and it shows up with an error message on the site. I am about to pull my hairs out trying to figure this out. Please someone help!