Mental Math

[Cellostar]

My daughter has memorised her number bonds upto 20, her answers although accurate are not fast enough. However, right now, we are struggling with applying those number bonds to improve the pace with which she can do mental math. She can quickly/easily do e.g. 33 + 4 (essentially within the 10 ones) or those with zero ones e.g. 33 + 20 but she is struggling to quickly do such as 33 + 25. Subtraction also seems particularly challenging if it goes into the previous 10s e.g. 65 - 7, but can do 65 - 4 etc.

How do I get her to improve her speed of recall, understanding and also progress quickly in mental maths. I am losing the plot with her at times.

Thanks

Practice and more practice, and keep telling her she can do it. The brain is good at recognising patterns, so it will come in time if she perseveres.

Oh yes, and stop losing the plot with her. She’ll do it faster with encouragement rather than threats.

She can quickly/easily do e.g. 33 + 4 (essentially within the 10 ones) or those with zero ones e.g. 33 + 20 but she is struggling to quickly do such as 33 + 25

It sounds like she basically 'gets' place value so understands that 33 is 30+3, which is why she can do 33+4 as it is the same sum as 3+4 (+30). Equally she can do 33+20 because it is the same sum as 30+20 (+3).

So why can't she do 33+25, which she could break up into 30+20, + 3+5, each step of which she has shown to understand and be able to apply? Is it overload of working memory? Can she do it quite easily when written down?

If it is a working memory issue, but she doesn't have general working memory difficulties, then probably she just needs to practise each individual step more, so that it becomes automatic and stops requiring so much working memory.

This may be controversial, but I found that column addition/subtraction provides endless practice for single-digit addition and subtraction. Plus it reinforces place value. (People may advise against introducing column methods before being solid on the 'basics' but in my limited experience introducing column methods provided all the practice in the world needed to become solid on the basics. Provided the 'understanding' was there, just not the fluency/speed.)

DS played the Dragonbox app 'Big Numbers' obsessively for a while, after that he was fast and fluent in single-digit sums, had place value re-inforced, AND had learned column addition/subtraction. All while playing a game and barely noticing that it involved maths! It is a 'world building' game where you start with one apple tree, have to pick the apples (and add them up yourself), invest into new apple trees to get more apples and eventually into other stuff like a fishing lake, bakery, gold mine, .... and you are always adding up the resources you collected, and subtracting them when you're using them to 'buy' something.