RPN stands for Reverse Polish Notation. Reverse Polish Notation was developed in 1920 by Jan Lukasiewicz as a way to write a mathematical expression without using parentheses and brackets. It takes a few minutes to learn RPN but you will soon see that this entry method is superior to the algbraic format.
1 4 / p # Divide 1 by 4 and print the result 0 # Set the precision to 0 decimal places 1 k # Keep 1 decimal place 1 4 / p # Divide 1 by 4 and print the result with 1 decimal place 3 k # Keep 3 decimal places 1 4 / p # Divide 1 by 4 and print the result with 3 decimal places 16 63 5 / + p # Divide 63 by 5, add 16, and print the result 16 63 5 + / p # Add 63 and 5, then divide by 16 and print the result" | dc
echo -e "1 4 / p\n0\n1 k [ Keep 1 decimal place ]s.\n 1 4 / p\n3 k [ Keep 3 decimal places ]s.\n 1 4 / p\n16 63 5 / + p\n16 63 5 + / p" | dc
printf '%s\n' "16i[q]sa[ln0=aln100%Pln100/snlbx]sbA293A207[rewop]swsnlbxq" | dc
echo -e "1 4 / p\n0\n1 k\n 1 4 / p\n3 k\n 1 4 / p\n16 63 5 / + p\n16 63 5 + / p" | dc