It sounds like you want to solve for t.
We have some unknown number t divided over 2.5
To isolate t, we undo what is happening to it. We undo the division. So we multiply both sides by 2.5
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4 = t/2.5
2.5*4 = 2.5*t/2.5 .... multiplying both sides by 2.5
10 = t
t = 10 ... answer
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As a check, we replace t with 10 and we should get the same number on both sides
4 = t/2.5
4 = 10/2.5
4 = 4 ... the answer is confirmed
