Hi muddy:
I think this is normal (remember they're still working this all out - and need a lot of practice/ familiarization with concepts). I also think practice will really help sort a lot of this out.
So some great free maths websites:
woodlands junior school MATHS ZONE: resources.woodlands-junior.kent.sch.uk/maths/ - just select area you want to work on and there are fantastic links to resources/ games.
Cool maths for kids: www.coolmath4kids.com/ - my girls primarily play games - but there are some lessons there as well - which may help when you're stuck on ideas of explaining how to do something.
Maths Champs: www.mathschamps.co.uk/
As your DD is Y2 - BBC KS1 Bitesize (which prepares students for KS1 SATs) has a maths section with good practice there: www.bbc.co.uk/bitesize/ks1/
If your school uses education city or My Maths: there are free games on this as well which provide good practice.
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Strictly speaking for KS1 (end Y2) notionally the benchmark is x2, x5 and x10 tables. From Year 3 the remainder of the times tables will be tackled and Gove is pushing for all times tables to x12 to be known by time child turns age 9 (sometime in Y4).
So - as your questions somewhat relate to x5 and x4 tables my longwinded answer below relates to how to teach times tables in general:
50 + 5 = 60 - is slightly worrying and does sound like they don't quite know their 5s solidly. It's both counting by intervals - 5 - 10 - 15 - 20 - but it's also knowing that multiple additions is the same thing as multiplication.
Sometimes songs help.
an olde but goody:
If your DD enjoys & gets halving/ doubling - then you're really well on your way to learning all the times tables.
So with 5x table - the trick can be to know what it is x10
i.e. 8 x 10 = 80 and then halve it - 1/2 of 80 = 40 - so 8 x 5 = 40.
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doubling comes in handy for 4x table (so referring to 6 x 4 = 36 mistake)
if your DD knows 2 x 6 = 12 and can double - than 4 x 6 is the same thing as 2 x 6 = 12 and then double that answer (2 x 12) = 24!
EASY when you know how.
Doubling works for x8 (same family 2/4/8):
if you know 2s - then it's the answer for the 2s times table and then double and double again
so if you DD doesn't like the look of 4 x 8 - try 4 x 2 = 8, double again = 16 and double again = 32 which is 4 x 8.
so that's 2/4/8 and 5/10 down.
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if you haven't or the school hasn't - do take time now to explain magic of x0 (anything x 0 = 0 or 1,999,999 x 0 = 0) and 1 is like a mirror - anything x 1 is itself - 999 x 1 = 999.
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now if your DD knows 3s (great song again from school house rock to help here: )
doubling helps with both x6 and x12 tables:
so for x6 table just double answer from x3 table- so 3 x 6 is the same thing as 3 x 3 = 9 and double that answer (9) - to give you 18 - 3 x 16 = 18.
for x12 table - you can double x3 table answer and double again (same method as for x8 table with x2 table).
so 3 x 12 is the same thing as 3 x 3 = 9, double that = 18, double that = 36 - so 3 x 12 = 36.
Another way of thinking of the x12 table is to add facts for x10 table and x2 table. so 3 x 12 = (3x10) + (3 x 2) = 30 + 6 = 36.
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so that's your x0, x1, x2, x3, x4, x5, x6, x8, x10, x12 tables down
that leaves x7, x9 and x11
let's ignore 7 (it's a swine) and look at x9 and x11.
x9 is lovely for patterns
1 x 9 = 09
2 x 9 = 18
3 x 9 = 27
4 x 9 = 36
5 x 9 = 45
6 x 9 = 54
7 x 9 = 63
8 x 9 = 72
9 x 9 = 81
10 x 9 = 90
pattern doesn't work beyond this but not to worry
So looking at this pattern you note two things:
The number in the tens column is always one less than what you're multiplying 9 by. So in 5 x 9 - the answer starts 4-. Then the second pattern gives you the remainder of the answer - the digits in the 9s times table (whatever you multiply 9 by - even 1,999,999) always add up to 9.
so back to 5 x 9 - we know the tens digit is 4 - so what + 4 = 9 - why that's 5 - so the answer is 45 - 5 x 9 = 45.
up to 10 x 9 - there is one more trick. Turn your hands so that both palms are upwards and the thumbs are on the outside. Start with left hand and number each thumb/ finger starting with left thumb = 1, to left pinky = 5 to right pinky = 6 and right thumb = 10. Now use your hands as a x9 calculator. Let's try 4 x 9. Fold over your 4th finger - that's your left ring finger. you'll see that you have 3 fingers up to the left of the finger (that's your tens digit) and six fingers up to the right of your ring finger (that's your units digit) - so that makes 36. 4 x 9 = 36.
now moving on
11 x 9 = 99 (either using 11s tricks - which I'll explain below) - or knowing 10 x 9 = 90 and 9 x 1 = 9 so 90 + 9 = 99
12 x 9 (you can either do the double and double again trick for 3 times table - 3 x 9 = 27; double that = 54 and double that = 108) or you can add 10x table and 2 x table facts together: so 12 x 9 = (10 x 9) + (2 x 9) = 90 + 18 = 90 + 10 + 8 = 100 + 8 = 108
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11s are fun
first off same thing as 1x table - anything x1 is itself - so up to 11 x 9 you just write the digit you're multiplying 9 by down 2 times.
1 x 11 = 11
2 x 11 = 22
3 x 11 = 33
...
9 x 11 = 99
then there's a trick - for two digit numbers x 11 separate the first and second digit and then put their sum in the middle.
so for 10 x 11 - separate 1 and 0 and put sum in middle: 1 - (1 + 0) - 0 = 110
and it works regardless of two digit number:
23 x 11 = 2 - (2 + 3) - 3 = 253
you will have to do some carrying over if the number in the middle >9
so for example;
29 x 11 = 2 - (2 + 9) - 9 = 2 - (11) - 9 = (2+1) - 1 - 9 = 319
gosh that means we know all times tables to x12 but 7.
In fact thinking about it we know the 7x table - because we've done it with x0 - x6 and with x8 - x12 - we just need 7 x 7.
I'm afraid there is no trick - you just have to learn 7 x 7 = 49 - however I find it helps to remember that 7 x 7 is a swine - which of course rhymes with 49.
And that's your lot.
Why is learning this important. Well I think that has been summed up best by this blog: www.greatmathsteachingideas.com/2014/01/05/youve-never-seen-the-gcse-maths-curriculum-like-this-before/ - the second image shows that the entire GCSE maths curriculum is largely underpinned by sound knowledge of multiplication/ division of whole numbers.
maths is full of patterns/ tricks - so learning them/ recognising them helps a lot. But it also is ideally suited to video games - so practice can take the form of playing. My DDs will happily play maths games whilst I'm cooking dinner and don't even realising they're learning/ practicing.
HTH