Hi AnxiosElephant:
A really great idea is to try counting games - snakes and ladders is perfect. Play it forwards for addition and backwards for subtraction.
Dice games are also good. Use 2 dice (so addition up to 12) and have your DD add the two dice. Use fingers or you can use buttons, candies, etc.. We like to play it with raisins or skittles and eat them when we are correct. Add more dice for bigger numbers when ready. Can be altered for subtraction as well - same idea - just subtract smaller from larger number or use 3 dice and subtract single die from two dice total.
If you'd like to see how your child is doing against the national curriculum standards - you might consider buying workbooks. These are great to have to hand when waiting at the doctors/ dentist/ etc... or for in the car. Most book shops/ good newsagents carry a range of these. Some are by key stage - which is a bit unfair as your DD has only started KS1. So may be better to target books by school year (Y1) or age (5 - 6). However my feeling is to hold off on this just now, until Y1 is nearly complete.
I should add that this is 'early days' for maths. Y1 is just starting so you should be looking at getting good strength adding numbers up to at least 10 - aiming for adding up numbers to 20-30 by end of year. And you might be thinking about the same with subtraction, depending on how well the addition is going.
I have found keeping it visual (but avoiding coins because they have numbers on them) does help. So use buttons, cookies, etc... to help your child visualise the numbers they are adding and subtracting.
If you feel you need more structured support - we found Mathsfactor (subscription) incredibly useful as well as KS1 bitesize maths excercises (which are free). We also like tux of math command - open source free software you can download [http://tux4kids.alioth.debian.org/tuxmath/] - (Use PLAY ALONE/ SPACE ACADEMY - and just select the type of sums you'd like to work on - the list is long so use the arrow keys at bottom right to scroll through). It's like space invaders - and is great fun.