Working with Decimal Numbers

October 10, 2016

Students learn how to use place value to add, subtract, multiply and divide with decimal numbers using the column method. As learning progresses they learn how to round to a given accuracy and use multiplication to solve a range of real life problems.

This unit takes place in Year 7 Term 3, and follows on from place value.

Working with Decimal Numbers Lessons

Addition with decimals

Subtraction with decimals

Multiplication with decimals

Dividing with decimals

Multiplication using the grid method

Multiplying Decimals using the Grid Method

Multiplication problems

Rounding to a decimal place

Prerequisite Knowledge

Multiply multi-digit numbers up to 4 digits by a two-digit whole number using the formal written method of long multiplication
Divide numbers up to 4 digits by a two-digit whole number using the formal written method of long division, and interpret remainders as whole number remainders, fractions, or by rounding, as appropriate for the context
Solve problems involving addition, subtraction, multiplication and division
Multiply one-digit numbers with up to two decimal places by whole numbers
Use written division methods in cases where the answer has up to two decimal places

Key Concepts

Students should have a good understanding of the place value table to add and subtract with decimal numbers.
When multiplying with decimal numbers students should be able to use a range of range of written methods.
Estimations should be made when dividing and multiplying with decimals.
When rounding to a decimal place the number is rounded up if it is exactly midway between two numbers.

Working mathematically

Develop fluency

Consolidate their numerical and mathematical capability from key stage 2 and extend their understanding of the number system and place value to include decimals

Reason mathematically

Extend their understanding of the number system; make connections between number relationships

Solve problems

Develop their mathematical knowledge, in part through solving problems and evaluating the outcomes, including multi-step problems
Develop their use of formal mathematical knowledge to interpret and solve problems, including in financial mathematics

Subject Content

Number

Understand and use place value for decimals, measures and integers of any size
Order positive and negative integers, decimals and fractions; use the number line as a model for ordering of the real numbers; use the symbols =, ≠, <, >, ≤, ≥

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