Tenths and hundredths in decimal numbers

Required materials

• tape measure
• pencil and paper

See Materials that come with this resource to download:

• Tenths and hundredths in decimal numbers activity (.pdf)

What to do

Check that your child knows how to use a tape measure.

Help your child to use the tape measure to find the heights or lengths of objects around the home.

Draw a table to make a list of objects to measure and record heights or lengths using metres and centimetres.

Check that your child understands there are 10 tenths in 1 metre. This is the same as 10 cm is a tenth of a metre.

Using the table look at the height of an object and ask your child:

• How many tenths are in the number?

Your child can check this by using the tape measure to count the number of 10 cm in the length by counting in tens 10, 20, 30 etc.

Check that your child understands there are 100 hundredths in 1 metre. This is the same as 1 cm is a hundredth of a metre.

Ask your child:

• How many hundredths are in the number?

Again your child can check by using the tape measure to see how many centimetres are in the length.

Once you have completed the measurements using the tape measure, look at the numbers and talk about the patterns you can see.

What to expect your child to do

• Your child should be able to say how many tenths and hundredths are in decimal numbers.
• There are 10 tenths in a whole, and 100 hundredths in a whole.

Variation

• Decimal numbers can also be found by measuring the weight of objects on kitchen scales and recording these as kilograms and grams.

He kupu Māori

Kia mataara

Be careful with the correct way of saying numbers with two and three decimal places. 0.25 is not said as "kore ita rua tekau mā rima (zero point twenty-five)" because saying rua tekau (twenty) is incorrect, misleading and confusing. The correct way of saying it is to say each individual digit: "kore ira rua rima (zero point two five)".

He whakawhitinga kōrero

• Titiro ki te ruri. Tohua te kotahi mita (1 m) me te tekau mitarau (10 cm). Ko te tekau mitarau te hauaha o te mita? (Look at the ruler. Point to a metre and 10 centimetres. What fraction of a metre is 10 cm?)
• Inea te teitei o te tēpu mahi, ka tuhi ai ki te tūtohi. (Measure the height of the work bench and write it in the chart.)
• E hia katoa ngā hautekau kei roto i tēnā tau? Tuhia ki te tūtohi. (How many tenths are in that number? Write it in the chart.)
• Tirohia te ruri mita. Tatauria ngā hautekau mita kei roto i te kotahi ira rua rima mita. (Look at the metre ruler. Count the tenths of a metre in 1.25 metres.)
• Ko te kotahi mitarau te hauaha o te mita? (What fraction of a metre is 1 cm?)
• E hia katoa ngā haurau kei roto i tēnā tau? Tuhia ki te tūtohi. (How many hundredths are in that number? Write it in the chart.)
• Tirohia te ruri mita. Tatauria ngā haurau mita kei roto i te kotahi ira rua rima mita. (Look at the metre ruler. Count the hundredths of a metre in 1.25 metres.)

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