Multiplying and dividing algebraic fractions
Multiply and divide algebraic fractions: factor, cancel, turn division into multiplication by the reciprocal, and say which values of the letter are not allowed.
- Germany: grade 8
- Russia: grade 8
Guide
In the Russian programme this is Grade 8 algebra, chapter "Rational fractions": multiplying and dividing fractions, a fraction to a power, transforming rational expressions.
To multiply fractions, multiply the tops and the bottoms: ab·cd = acbd. It is easier to factor first and cancel, then multiply what is left.
To divide by a fraction, multiply by its reciprocal: ab : cd = ab·dc. The divisor must not be 0, so its zeros are not allowed either.
A fraction to the power n has top an and bottom bn. Always say at the end which values of the letter are not allowed.
On the board tap an expression and Split to get its factors, then tap a factor above the bar and an equal one below to cancel. Type the answer on the keypad; the fraction key puts what follows under the bar.