Definitions to know for this unit: estimate overestimate underestimate order of operations
Topics: 2.1--Add and Subtract Decimal Numbers There are different ways to estimate the answer to any addition or subtraction question, including front-end estimation and relative size. When you add or subtract decimal numbers, align the decimal points, then add or subtract digits with the same place value.
2.2--Multiply Decimal Numbers You can use front-end estimation and relative size to estimate the answer to a multiplication question. When using a calculator, estimate to make sure your answer is reasonable. You can multiply decimal numbers the same way you multiply whole numbers and then use estimation to place the decimal point.
2.3--Divide Decimal Numbers Thee is more than one way to estimate the answre to a division problem. When using a calculator, esimate to make sure your answer is reasonable. You can divide decimal numbers the same way you divide whole numers and then use estimation to place the decimal point.
2.4 --Order of Operations and Decimal Numbers The order of operations is used with operations that involve decimals. The order of operations is as follows:
Do the work in brackets first.
Multiply and divide in order from left to right.
Add and subtract in order from left to right.
Brackets can be used to change the order of operations.