How are decimals used in everyday life?
The main use I can think of is in money. Money is expressed in decimal form.
Although for everyday use, we rely on inches, feet and yards for distance, other countries use decimal measures — millimeters, centimeters, meters and kilometers. Likewise, other measures in other countries and many scientific measures rely on the decimal system. For example, liquid medications are administered in cc (cubic centimeters) by volume.
This is just a beginning. I hope this helps. Thanks for asking.