Such a test would still give you over an entire minute per problem!
If it takes you more than a minute to do a problem like this, (even without any shortcuts!) then you just need to practice.
I fully believe if you do a dozen or so practice problems, you'll start to see some short-cuts of your own -- e.g. shorthand for some parts of the numeral, or some parts of the answer you can just write down without having to do any computation at all.
I suspect these short-cuts are probably better figured out on your own than taught. e.g. I could tell you that you didn't really need to write down the last 4 0's of each number in your scratch work, but I doubt me telling you would have the same impact as you figuring a short-cut out yourself after working through enough exercises. It's almost always easier to use your own short-cut than somebody else's short-cut. (even if they are essentially the same thing)