Discover Mathematics P4: Term 2, Unit 10, Lessons 1–4
GoalUse place value to the right of the decimal point and write decimals in standard, word and expanded forms.
New words
tenths place · the first place after the decimal pointhundredths place · the second place after the decimal pointexpanded form · a number written as a sum of the values of its digits
Explanation
The place value chart continues to the right of the decimal point. Each place is 10 times smaller than the place on its left: ones, then tenths, then hundredths. In 2.13 the digit 2 is in the ones place (2), the digit 1 is in the tenths place (0.1) and the digit 3 is in the hundredths place (0.03). Expanded form: 2.13 = 2 + 0.1 + 0.03. Word form: two and thirteen hundredths. A digit 0 keeps a place: 5.08 = 5 + 0.08 and is read five and eight hundredths, while 5.8 is five and eight tenths. When we read a decimal with hundredths, say the whole number, then the digits after the point as one number and name the last place.
2.13 = 2 + 0.1 + 0.03
Digit
2
1
3
Place
ones
tenths
hundredths
Value
2
0.1
0.03
Worked examples
3.45
Digit
3
4
5
Place
ones
tenths
hundredths
Value
3
0.4
0.05
Look at 3.45. The 3 is in the ones place, the 4 is 4 tenths = 0.4 and the 5 is 5 hundredths = 0.05. Expanded form: 3 + 0.4 + 0.05. Word form: three and forty-five hundredths.
5.08
Digit
5
0
8
Place
ones
tenths
hundredths
Value
5
0
0.08
Write 5 + 0.08 in standard form. There are no tenths, so a 0 holds the tenths place: 5.08. Read five and eight hundredths. 5.08 is not 5.8: 5.8 has 8 tenths.
Write 2 + 0.1 + 0.03 as a decimal: 2 ones, 1 tenth and 3 hundredths make 2.13. In words: two and thirteen hundredths, because 1 tenth + 3 hundredths = 13 hundredths.
Class activity
Decimal cards. Make three digit cards, for example 4, 0 and 7, and a decimal point card. Make every decimal you can with the point after the first digit (for example 4.07). Read each one aloud and write its expanded form.
Practice
1
What is the value of the digit 6 in 4.62?
The 6 is in the tenths place: 0.6 (six tenths).
2
What is the value of the digit 9 in 7.09?
The 9 is in the hundredths place: 0.09.
3
Write 8 + 0.3 + 0.07 as a decimal.
8.37.
4
Write twelve and five hundredths in numbers.
12.05 (a 0 holds the tenths place).
5
Nour writes five and six hundredths as 5.6. What is wrong? Write it correctly.
5.6 is five and six tenths. Six hundredths needs a 0 in the tenths place: 5.06.
