Importance of Place Value in Mathematics

September 1, 2016

Importance of Place Value in Mathematics

Understanding place value is important because it helps you understand the magnitude of numbers.  Because of place value we know 30 is 10 times bigger than 3 which is a hundred times bigger than 0.03.   This would not have been possible with Roman Numerals as they do not have a decimal point, or zero for that matter.  Egyptian numerals evolved to include unit fractions but with their complex hieroglyphs place value was still in its infancy.

In secondary school mathematics the place value table underpins so many fundamental mathematical concepts.  For students to begin to appreciate the size of a number or how to write numbers in words they need to have a secure understanding of its application.

At the start of every school year I like to go back to using the place value table with Year 7 and Year 8 students.

With Year 7s we use it to:

• Write numbers as words and vice-a-versa.
• Identify the value of a digit.
• Compare the size of numbers
• Creating minimum and maximum values using the same digits
• Multiply and divide a number by 10, 100, …
• Compare our number system to those throughout history
• Ordering decimals
• Adding and subtracting with decimals
• Simple multiplication and division
• Write a decimal as a fraction and mixed number
• Understanding number sequences

With Year 8s we use it to:

• Convert between fractions, decimals and percentages
• Multiply and divide a number by 1, 0.01, …
• Addition and subtraction with fractions and mixed numbers
• Finding a fraction and percentage of an amount
• Understanding the difference between discrete and continuous data
• Begin to write numbers using standard form
• Upper and lower bounds of measurement

For more information on teaching place value in Year 7 check out these lessons.

Alternative Number Systems

Comparing the size of numbers

Dividing a number by a power of ten

Writing numbers using words and digits

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