Multiply fractions - multiply, then simplify

To multiply fractions, we can just multiply the numerators, multiply the denominators, and then simplify at the end. So for this first question, []our numerator will be 3 times 8 and our denominator will be 4 times 9, []so that gives us 24 over 36. But how can we simplify 24 thirty-sixths? Both 24 and 36 are multiples of 12, so if we divide both the numerator and denominator by 12, []we can simplify to 2 thirds. So pause the video, and see if you can follow the same steps to work out 5 twelfths times 3 tenths and 7 tenths times 5 tenths. So if we []multiply the numerators and denominators, []we get 15 over 120, but we can simplify this question: we might spot straight away that 15 and 120 are both multiples of 5, so dividing both the numerator and denominator by 5 gives us []3 over 24 – but now, we can simplify this fraction further, because both 3 and 24 are multiples of 3, so if we divide both the numerator and the denominator by 3, []we get 1 eighth: so when you’ve simplified a fraction, it’s always necessary to check whether you can simplify it further: here, we could have divided 15 and 120 by 15 to get 1 eighth straight away, but because we divided the numerator and denominator by 5 first, we then had to divide the numerator and denominator by 3. Finally, for this last question, []we have 7 times 5 over 10 times 10, []so that’s 35 over 100, which we can simplify to []7 twentieths.