Whole Numbers and Place Value — Victorian Year 4 Maths

Q: How do you round a number to the nearest 10?

Look at the ones digit. If it is 4 or less, round down to the ten below; if it is 5 or more, round up to the next ten. So 73 rounds to 70 and 86 rounds to 90. A number line from one ten to the next makes this easy to see.

Q: What happens to a number that is exactly halfway?

A number exactly halfway always rounds up, so 25 becomes 30 and 7500 becomes 8000. Common mistakes are checking the wrong digit and changing a number that is already a multiple of ten: 380 stays 380 to the nearest ten. At home, round the prices on a receipt or the distances on road signs.

Q: Why does rounding matter in Year 4?

Rounding is how students estimate. Before adding $48 and $31, rounding to $50 + $30 shows the total should be about $80, so an answer of $179 must be wrong. It is used again in the Addition, Subtraction and Money topics.

Rounding whole numbers to the nearest 10, 100 or 1000, including halfway numbers, prices, distances and crowd sizes. One subtopic and 20 questions with worked solutions, aligned to VC2M4N07.

1 subtopics

20+ questions

Whole Numbers and Place Value in Victorian Year 4

This topic is about rounding: swapping a whole number for a tidy nearby multiple of 10, 100 or 1000. Rounding is the tool students use to estimate answers and to check that a calculation is sensible, so it comes before the estimating work in Addition, Subtraction and Money.

Its one subtopic, Round Numbers to the Nearest 10, 100 or 1000, covers the digit to check, number lines, the halfway rule and working backwards from a rounded value. Whole Numbers and Place Value is one of the 20 topics in Victorian Year 4 Maths and belongs to the Number strand. It comes under Victorian Curriculum code VC2M4N07, about using estimation and rounding to check calculations. Rounding leads on to estimating with larger numbers and with decimals.

Subtopics

1 subtopics · Sorted by recommended order

Round numbers to the nearest 10, 100 or 1000

20 questions

Whole Numbers and Place Value: common questions

How do you round a number to the nearest 10?

Look at the ones digit. If it is $4$ or less, round down to the ten below; if it is $5$ or more, round up to the next ten. So $73$ rounds to $70$ and $86$ rounds to $90$. A number line from one ten to the next makes this easy to see.

Which digit do you check when rounding to the nearest 100 or 1000?

Look at the digit to the right of the place you are rounding to: the tens digit for the nearest hundred and the hundreds digit for the nearest thousand. If it is $5$ or more, round up; if it is $4$ or less, round down. So $3640$ is $3600$ to the nearest hundred and $4000$ to the nearest thousand.

What happens to a number that is exactly halfway?

A number exactly halfway always rounds up, so $25$ becomes $30$ and $7500$ becomes $8000$. Common mistakes are checking the wrong digit and changing a number that is already a multiple of ten: $380$ stays $380$ to the nearest ten. At home, round the prices on a receipt or the distances on road signs.

Why does rounding matter in Year 4?

Rounding is how students estimate. Before adding $\$48$ and $\$31$, rounding to $\$50 + \$30$ shows the total should be about $\$80$, so an answer of $\$179$ must be wrong. It is used again in the Addition, Subtraction and Money topics.

Which curriculum codes cover Whole Numbers and Place Value in Victorian Year 4?

The rounding subtopic comes under Victorian Curriculum code VC2M4N07, which is about using rounded numbers to estimate and to judge whether an answer, including a money calculation, makes sense.