Question 1152073
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Use mental math to find the total amount of the bill.
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Do the sum of the given items using their prices, in your head.  


Can you do this without writing any steps on paper?
{{{2.75+8.50+3.85+1.15}}}



You could try this:
Look at the whole part of EACH number.
2, 8, 3, 1;
You can understand their sum:  14.


What else?  Take the fraction part of each of the given numbers:
0.75, 0.50, 0.85, 0.15;
It may take a little more thinking, but can you figure the sum of these without writing anything?
{{{0.75+0.5=1.25}}}
AND
{{{0.85+0.15=1.00}}}
AND then 
together, the fractions parts sum to 2.25.



And you can finish the rest.