Simple Multiplication error

I have following data

A B C D
2kg 7.50kg 2gm 5gm

5 7 3 6.2

=2*A2 =7.50*B2 =2*C2 =5*D2
10 52.5 6 31

How to formulate a formula without using manually assigning numeric value for A1:D1 rows in A3 during calculation by A2:D2 as in A1:D1 as there is a alpha numeric that produces an error on doing so.

Is there any way to link A1:D1.This is a sample for A2 as there are many rows which is needed to be multiplied by A1:D1 but due to alpha numeric it is difficult to do calculation as manually I have to assign numeric part for A1:D1.

With Best Rgds,

Thanks all of you.