Hi, I'm Susan Defibaugh and I teach fifth grade at Parkside Elementary School. Today,
I am going to model subtraction of decimals using a number line.
Today's problem John went to the market to get some fruit.
The apples weighed
three and twenty two hundredths pounds the oranges weighed one and eighty four hundredths pounds.
How much more did the apples weigh than the oranges?
Okay, since I know how much the apples weigh and I know how much the oranges weigh
I'm looking to see how much more the apples weigh than the oranges. So I'm going to use subtraction.
I'm going to start by drawing a number line.
And I will mark three and twenty two hundredths
to represent how much the apples weighed.
Then I am going to show taking away one and land at two and twenty two hundredths.
I am going to take away 8/10.
Using place value, I know that two and two tenths is the same as twenty two tenths.
Twenty two tenths minus eight tenths equals fourteen tenths or 1 and 4/10.
I keep the two hundredths to get one and forty two
hundredths.
Last I will take away four hundredths.
I can simply do 42 minus four and end on one and thirty eight hundredths.
Now I'm going to write an equation to match the story.
Three and twenty two hundredths minus one and eighty four hundredths
equals one and thirty eight hundredths.
So looking back at my question how much more did the apples weigh than the oranges,
The apples weigh one and thirty eight hundredths pounds more than the oranges.
