19 is only 1 away from 20, so you prefer to start by multiplying 20 times 5, which equals 100. Then we need to take away a squadron of 5, because there are actually only 19 squadrons, not 20. 100 take ...

A decimal number is any number made up of the digits 0 to 9. This can include whole numbers and numbers less than 1. You can use a decimal point to show which digits are whole numbers and which are ...