How To Add Fractions With Like Denominators Video

now we'll look at two examples of subtracting fractions with like denominators. with subtractingfractions with like denominators, the denominator is going to stay the same and then we subtract the numerators. so for seven-eighths minus three eighths, the denominator's going to stay eight

How To Add Fractions With Like Denominators Video, and then for the numerator we would have seven minus three which is equal to four. once we find thisdifference we do want to see if we can simplifythis fraction. well, four and eight do share a common factor of four.

to show this we could write four as onetimes four and eight as two times four so i can actually see the common factor of four. this step isn't necessary but if we do show this, we can easily seewhy this simplifies to one-half. let's also take a look at the model forthe subtraction problem. if we view this large rectangle as one unit,divided it into eight equal parts. this would be the model for seven-eighths, thiswould be the model for three-eighths. and because our denominator is the same, that means each of these pieces is the same size.

so if we have seven pieces and subtractthree pieces that will leave us with four pieces, where each piece represents one-eighth, leaving us with the difference of four-eighths modeled here. so here's the model for four-eighths but we can also show this is equal toone-half, if we divide this rectangle into two equal pieces. notice how we have half of the rectangle shaded verifying our difference is equal toone-half. for four-ninths minus one ninth, again the denominator is going to stay at nine, the numerator is going to be four minus

one which is equal to three. but again, this fraction is going to simplify because three and nine share a commonfactor of three, and again just to show this we could write three as one times three and and nine is three times three. three overthree simplifies to one, leaving us with oursimplified difference of one-third. again if you take a look at the model for the subtraction problem this would be the model for four-ninths,this would be the model for one-ninth and again because the denominators are the same

these pieces are the same size. four pieces minus one piece would leave us three pieces, where each piece represents one-ninth. therefore, this difference is three-ninths, modeled here but because this entire fracture represents one. unless we divide into three equal pieceshere and here, this will simplify to one-third, which we had here as well. okay, i hope this helps.