"I am sending ten blue shirts."

Translation: Saya mengirim sepuluh kemeja biru.

[SurferDrea]

Should it not be kemeja-kemeja?

[Rick392366]

No.
There is already an indication of plurality ('sepuluh').
In such a situation, you don't reduplicate the noun.
Examples:
'Saya punya satu kemeja' = I have one shirt.
'Saya punya sepuluh kemeja' = I have ten shirts.
'Saya punya banyak kemeja' = I have many shirts.

[TuanDung761469]

Is "Saya mengirim sepuluh kemeja yang biru" acceptable?

[Away54]

If you want to add "yang", the formal way is: "kemeja yang berwarna biru".

[UltraSlacker]

Why is saya sedang mengirim sepuluh kemeja biru wrong?

[Away54]

"Saya sedang mengirim sepuluh kemeja biru" = I am sending ten blue shirts.

It should be accepted as well.

[VincentQuerta]

Why is baju wrong??

[Away54]

"Baju" = "clothes" but it should also be accepted as "shirts". At least, it is colloquial. Some Indonesian people often say "baju" for "kemeja" in the oral situation.