please help compare 2 childs savers accounts

Midori_2

hi,
I am having trying to compare 2 savings accounts for my children, they currently have smart accounts paying 5.7% but I have noticed the Halifax regular saver at 10%. The only problem is my eldest has about £750 in his account and I would only be able to transfer over £100 a month maximum and I wondered if I should open one of these accounts and pay £100 out of the smart account into the Halifax account each month.

I was trying to work out £750 at 5.7% for a year compared to £100 (increasing by £100 till the £750 is used up then £20 a month) at 10% for a year. If that makes any sense!

Any help working this out would be greatfully received as my brain is slowly melting here.
Many thanks