The smiths spent 18% of the monthly income on food. the income in may was $3500.00. how much did they spend on food

To calculate the percentage of a quantity you need to multiply the percentage times the quantity, keep in mind that a percentage is a ratio of a number over 100, so we have:
18% = 18 out of a 100 = 18/100
and we propose the multiplication:
(18%)($3500) = (18/100)($3500)
= 18*3500/100
= 630
therefore, 18% of $3500 is $630, so they spent $630 on food
 

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