# Four everyday Maths tips and tricks from celeb whizzes

## Is Maths anxiety making you feel less than 100%? Never fear, the pros are here!

These numerical hacks will make it easier for you and can be applied in everyday situations. We’ve asked University Challenge whizz Bobby Seagull, Money Saving Expert Martin Lewis and Countdown's Rachel Riley to share their Maths tips and tricks for your revision needs.

## Bobby's top tip for multiplying 2-digit numbers by 5

Double-digits can be pretty intimidating, especially when you know they're going to multiply. Don't fret, Bobby has a nifty trick for multiplying odd and even numbers by 5.

• For an EVEN number, e.g. 42 x 5

• first divide 42 by 2 to get 21

• multiply it by 10 (or add a 0) to get 210

• so 42 x 5 is 210.

• For an ODD number, e.g. 37 x 5

• divide 37 by 2 to get 18 with 1 remainder

• add the remainder to the end (so 1 remainder is 5)

• therefore, 37 x 5 is 185.

## Martin's top tip for measuring a discount

Don't be fooled by the double discount either... We've all been there, but Martin's got your back. Learn some money Maths and avoid fumbling the figures.

To figure out whether that 20% off price tag is worth it:

• imagine a coat that costs £100 and is reduced by half
• it now costs £50
• 20% of £50 equals a further £10 reduction
• the cost is now £40
• thanks to the double discount, your 20% off is actually worth £10 off the £100 coat.

## Rachel's top tip for working out percentages

Speaking of fumbled figures, have you ever felt the pressure to quickly work out money off during a flash sale? Practise Rachel's method for finding percentages and you'll know if you've got a real bargain on your hands in no time.

• To work out a 20% discount, take the final nought off the price

• this will give you 10%

• for 20% off, double it

• for 30% off, triple it. Simple.

## Add a Rachel Riley bonus hack for the 11 times table!

Check out another double-digit multiplication trick with Rachel's maths hack for the 11 times table.

• To multiply 11 by a 2-digit number, e.g. 11 x 31,

• first separate the 3 and the 1

• add them together and put the total in the middle

• so 11 x 31 is 341.