Englishfor English speakers
exchange
Verb
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Two people exchange two things when each person gives a thing to the other person. They can exchange two things, or they can exchange a thing for money.
The children can exchange toys so that each child has a new toy to play with.
exchange
Noun
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An exchange is the act of exchanging.
I did well in that exchange. Now I have three good new books, and I only paid a little money.
ratio
Noun
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A ratio is the comparison in size or number between two things. It is written mathx:y/math and read mathx/math to mathy/math. It is the same as the fraction math\frac {x} {y}/math.
The ratio of men's jobs to women's is 8 to 1.
But Germany now has one of the highest ratios of spending to GDP in the European Community.
The low student/teacher ratio makes this a great school.