PC Advisor has TOP 10 Maths apps here: www.pcadvisor.co.uk/features/software/3380559/best-maths-apps-for-children/
Oxford School Improvement has top ten maths apps list here: fds.oup.com/www.oup.com/pdf/oxed/primary/top-10-maths-apps.pdf
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Not an APP - but can be downloaded to computer:
Timez Attack: www.bigbrainz.com/
There is a two level free version which we found was fine - but there are more expensive versions with other platforms you can buy. The programme starts by testing your times table knowledge and letting you start where you're at.
You can be a little boy or girl ogre.
Your mission is to run through a dungeon or castle and solve multiplication problems. They are presented vertically - so 4 x 4 for example - then to the side are blocks with blue dots for the repeated additions - so in this case 4 blocks with 4 blue dots. These turn into a blue ball which bounces on the floor and becomes a snail. You have to round up 4 snails - and then throw them against a wall. This counts up the fours - snail 1 - 4, snail 2 - count 8, snail 3 - count 12, snail 4 - count 16 (teaching you that multiplication is simply multiple additions). You then have to solve the vertical multiplication problem by typing in the answer - in this case 4 x 4 = 16.
At this point a medium-sized ogre comes out and quizzes you on this problem and two previous problems. Once you've passed the quiz you can continue exploring. Every so often a Giant Ogre comes out and quizzes you on all the past problems. It will record which problems you don't solve and give you those again on the next level.
Once you've worked through Times Attack - there is apparently an inverse multiplication game which is fun to play.
Now I should warn you this can be very stressful to play - but it makes you incredibly fast at your times tables. My girls both love it - but the youngest used to scream every time the bigger ogres came out.
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Mumsnet also has a link to mathschamp here: www.mathschamps.co.uk/#home - which has all sorts of games to help with multiplication/ inverse multiplication facts & building up speed.
HTH