I think bignum just gives you more precision but does not eliminate the problem.

To eliminate the problem you could use bigrat and use fractions.

Compare: 

perl -Mbignum -e ' printf "%20.17f\n", 20.1;'
20.10000000000000142

perl -Mbigrat -e ' printf "%20.17f\n", 20.1;'
20.10000000000000142

perl -Mbigrat -e ' printf "%20.17f\n", 20+1/10;
20.00000000000000000

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In reply to Re^2: floating point addition by morgon
in thread floating point addition by kresike

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