ABSTRACT
Fractions are also used everywhere in science, from radioactive decay rates to statistical analysis. Calculators are able to handle calculations with fractions. To multiply two or more fractions together, the numerators are first multiplied to give a single number, and this becomes the new numerator of the combined fraction. The denominators are then multiplied together to give the new denominator of the combined fraction. Ratio is a way of comparing amounts of something; it shows how much bigger one thing is than the other. Some practical examples include mixing paint, or sand and cement, or screen wash. Gears, map scales, food recipes, scale drawings and metal alloy constituents all use ratios. Two quantities are in direct proportion when they increase or decrease in the same ratio. There are several practical engineering laws which rely on direct proportion. Also, calculating currency exchange rates and converting imperial to metric units rely on direct proportion.
