4 is estimated to : 4.0
6.48 is estimated to 6.5 (or you can say 6.50 they are equivalent to the same thing)
6.48 ÷ 4 actual answer is 1.62 (or you can say "1.620" they are both equivalent to the same thing as well)
But, 6.5 ÷ 4.0 is estimated to 1.625