Transcript SCO A2: Students will be expected to interpret and model decimal

SCO A7: Students will be expected to
read and represent decimals to
thousandths.
Introductory Activity 1:
Draw a number line with a starting point of
2 and an ending point of 4.
Examine the following list of decimal
numbers so that you can properly ‘preheat’
your number line.
2.51
3.490 2.3 2.999
3.01 3.409
3.75
Next, place each decimal number at its
correct position on the line. Be prepared to
explain your thinking.
Introductory Activity 2:
Making the connection
between decimals and fractions:
Suzanne went to the store and bought 6.25
L of juice for a birthday party. How is this
amount read?
How is this amount read as a fraction? What
is another fraction we can use to represent
this amount?
How is the amount 4.75 kg read as a
decimal and as a fraction? What other
fraction represents this amount?
Introductory Activity 3:
Decimal numbers can be used to represent
very large numbers.
For example, the number 5.1 million
represents the number: 5 100 000
What large number does 3.4 million
represent? What large number does 3.5
million represent? What large number does
3.54 represent?
Introductory Activity 4:
Estimating and Reading Numbers
18.5 can be read as 18 and 5 tenths or more
usually as 18 and ½
How can the number 6.497 be read as a
fraction? What everyday fraction is this
amount close to? (about ____)
48.73 is about ????
12.254 is about ????
Student Activities
A7.1
Work with a partner. Take turns tossing
three dice. Make the largest number you can
using the digits to represent tenths,
hundredths, and thousandths. Show this
same number using base-ten blocks. How
much would need to be added to this
amount to make one whole?
Student Activities
A7.2
Examine the different displays of
combinations of base-ten blocks. Record the
five decimals shown if the large cube
represents 1 whole.
Student Activities
A7.3
Gasoline is priced at 75.9 cents per litre.
What part of a dollar is this?
Home heating oil is priced at 65.7 cents per
litre. What part of a dollar is this?
Student Activities
A7.4
Write the decimal numbers for “two
hundred fifty-six thousandths” and “two
hundred and fifty-six thousandths”.
Explain why watching and listening for
“and” is important when interpreting
numbers.
Student Activities
A7.5
Newspapers sometimes use decimal
numbers to record numbers. For example, a
newspaper might use 2.5 million instead of
2 500 000. Do you think this is a good idea
or not?
How might a newspaper show 4 300 000
using a decimal number?
What about 7 540 000?
Student Activities
A7.6
A student was given the instructions:
“Please cut 3.25 metres of ribbon for me.”
How many centimetres of ribbon is this?
How do you know?
Student Activities
A7.7
I was thirsty and drank 0.485 litres of water.
How much more would I have had to drink
to equal 0.5 L?
Student Activities
A7.8
Examine newspapers and magazines to see
when 0.5 and ½ are used.
Student Activities
A7.9
Write four different decimal numbers that
have tenths, hundredths, and thousandths.
Make base-ten pictures that would represent
these numbers.
For each amount, tell how much more
would be needed to have a whole cube.
Write this showing using a subtraction
sentence.