2. describe why, not just how, to round decimals
Thank You!Hi Angela,
If your students have calculated the area of a rectangle with integer sides by multiplying the integers then you can use this concept to represent the multiplication of fractions.
Suppose that you want to multiply 1/2 and 3/4. Draw a unit square and divide it in half in one direction and in quarters in the other. The region shaded in purple below has an area represented by 1/2 x 3/4
In this construction you divided the unit square into eight, equal sized rectangles so each rectangle represents one-eighth on the unit square. Hence the purple region is three-eights of the unit square so that 1/2 x 3/4 = 3/8
For your second question one example that immediately come to mind is with money. Suppose that you purchased something for $28.95 and you have to pay 7% tax. Then the tax is $28.95 x 0.07 = $2.0265. Since we don't have coins worth less than $0.01 we round the tax to $2.03.Cheers,