Typing numbers 5, 6, 7, and 8, is easy. 
Typing 4 and 9 is not too difficult either. 
But + and - and = are definitely more demanding! 
I really enjoyed our holiday in Aix-en-Provence (France). 
Could I have 4.5 lbs of potatoes, please? And 8 nice steaks topped with 9 slices of bacon. 
If you see 4 cats and 5 dogs, how many animals are there in total? 4+5=9. 
If 7+x=86, how much is x? 86-7=79. 
235-57=? Could that be too difficult? 
4+7+588=599. Is that correct, John? 
Ninety-five monkeys sat in the tree. 95 monkeys is a lot! 
If 59+44-y=99 and 566-74+y=496, how much is y? 
Did you know that the burnished-buff (rufous-crowned) tanager is a bird? 