relating to or expressed in a system of counting based on the number ten

If you calculate the result to two decimal places (= give two numbers after the decimal point, as in 3.65), that should minimize any possible errors. 如果将计算结果保留两位小数，就会最大限度地减小可能的误差。

a number expressed using a system of counting based on the number ten

Three fifths expressed as a decimal is 0.6. 3/5用小数表示就是0.6。