Place value to thousandths

What it looks like when your child can do it

• — Looking at 3.472, your child says the 7 is worth seven hundredths, or 0.07.
• — Your child writes one dollar and seven cents as 1.07, not 1.7, and can say why.
• — Your child knows 2.5 and 2.50 are the same amount, but 2.5 and 2.05 are not.

How to teach it at the kitchen table

1. 01

   Start with money on the table

   Put down 4 dollar bills, 6 dimes and 3 pennies, and write 4.63. The dollars sit left of the point. Dimes are tenths of a dollar and pennies are hundredths.

2. 02

   Name every place out loud

   Left of the point: ones, tens, hundreds. Right of the point: tenths, hundredths, thousandths. Each place is worth ten of the place to its right, so ten hundredths make one tenth and ten thousandths make one hundredth.

3. 03

   Read decimals as numbers, not strings of digits

   Say 5.038 as five and thirty-eight thousandths, not five point zero three eight. Reading it this way tells your child what the number is worth.

4. 04

   End zeros change nothing, middle zeros matter

   4.6 and 4.60 are the same number, because the extra zero only says there are no hundredths. 4.06 is a different number: four and six hundredths, which is less than 4.6.

You will need: A few dollar bills, dimes and pennies · Paper for a place value chart

Try it together

1. Try 1

   Write 3.472 and ask what the 7 is worth.

   Listen for  Seven hundredths, or 0.07. If your child says seventy, they are reading the digits like a whole number. Point to each place and name it: ones, tenths, hundredths, thousandths.

2. Try 2

   Ask your child to write five and thirty-eight thousandths as a decimal.

   Listen for  5.038. The 38 has to end in the thousandths place, so a zero holds the tenths place. Writing 5.38 is the common slip.

3. Try 3

   Ask whether 2.5 and 2.50 are the same, and whether 2.5 and 2.05 are the same.

   Listen for  Yes to the first, no to the second. 2.5 is five tenths past 2, and 2.05 is only five hundredths past 2.

4. Try 4

   Ask for the number that is one tenth more than 6.95, then the number that is one hundredth more than 6.95.

   Listen for  7.05 and 6.96. Adding a tenth pushes the tenths column past 9, so it carries into the ones. That carry is the part to watch.

5. Try 5

   Ask how many hundredths are in 0.3.

   Listen for  30 hundredths, because 0.3 is the same as 0.30. Three dimes are thirty pennies, and that picture helps.

Watch for

• — Reading the digits after the point as a whole number, so 0.45 seems bigger than 0.5 because 45 is bigger than 5. Writing 0.5 as 0.50 clears it up.

If it is not there yet

• — Go back to money. Build amounts with dollars, dimes and pennies and write each one down until tenths feel like dimes and hundredths feel like pennies.
• — Draw a place value chart with columns for tens, ones, the point, tenths, hundredths and thousandths, and write each digit in its own box.

A few days of this is normal, and it is time well spent. The lesson will still be there, and it will go faster.

Where this skill comes up

• Grade 6 Math Practice Workbook · Lesson 2

  Decimals: Add, Subtract, Multiply, Divide

  Needs it because placing the decimal point depends on knowing what each place is worth.