"Percent" means "per 100" or "over 100". So, to convert 0.068 to percent we rewrite 0.068 in terms of "per 100" or over 100.
Multiply 0.068 by 100/100. Since 100/100 = 1, we are only multiplying by 1 and not changing the value of our number.
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6.8/100 is 6.8 over 100 and means 6.8 per 100. 6.8 "per 100" means 6.8 "percent" or 6.8%
Therefore, we have shown that
0.068 = 6.8%