Create Total Measure with a Slicer

Hi guys, 

Fairly new to PowerBI so would be great if someone can enlighten me here on what formula I should use. 

Table columns: 

Date

Product Category

Quantity Sold

I did the following:

1. Created a measure called "Total Sold" which is the sum of the quantity sold column.

2. In visual, I added a slicer based on the Date - so that I can filter on quarters. 

3. In visual, I also created a matrix with Product Category as rows, and "Total Sold" as the first column. 

I want to:

a. Create a measure which calculates the total of quantity sold

b. Create another measure which calculates the % of total (so, will be Total sold Divided by the new measure created above.) 

For a., I used formula "calculate([Total sold], all ('table_name')). However, it looks like it removed all filters, including the one that came from the slicer and returned the total quantity, while I wanted it to return the total quantity for the selected quarter on the slicer. Can anyone please help? 

Thanks!