Is anyone reading this, good at maths please?

I'm trying to work out how much I'll have saved up by this time next year.

I'll have £460 every 4 weeks after all my bills come out of my account.

I want to put at least £300 every 4 weeks aside for Steve's car so that I've still got £160 every 4 weeks for myself.

I'll have £1,200 saved up in a different account by the end of next year which, in theory, I'm willing to add £1,000 of to the saved up money.

If I'm feeling generous, I'll add another £60 to the £300 for gifts but how much will I have saved up by next December?

I've already put £450 into the joint account to start things off right.

So, this is my maths... is it right though, please?

£300x12=£3,600
£3,600+£450=£4,050
£60x3=£180
£4,050+£180=£4,230
£4,230+£1,000=£5,230

Is it right though?  Have I included everything and done the adding ups right?