mysql - How to sum up these grouped rows that also have an order by -

imagine data in table:

amount/ number /type 100/ 1.2 / 120 / 1.2 /a 130/ 1.1 / 90 / 0.3 / 50/ 2.4 / b 150 / 1.9 /b 150 / 1.9 / b 

i want data in 2 groups 1 type a, 1 type b. within these 2 groups want them ordered price, ascending 1 , descending other. can do:

(select * `table` `type`='a' group `number` limit 10) union  (select * `table` `type`='b' group `number` limit 15) order `type`),  (case when `type`='a' `number` end) asc,  (case when `type`='b' `number` end) desc"; 

however problem want add types of same number.. 1.2 220/1.2/a, instead query 100/1.2/a... how add numbers amounts of same amount , same type?

thanks

this query want:

(select sum(amount) amount, number, type  `table`  `type`='a'  group `number` limit 10 ) union  (select sum(amount) amount, number, type  `table`  `type`='b'  group `number` limit 15 ) order `type`,            (case when `type`='a' `number` end) asc,            (case when `type`='b' `number` end) desc; 

as note: return 10 rows of , 15 rows of b after group by. i'm guessing want.

also, group by automatically order number. if want random order, add group rand() each subquery before limit.