Sum formula using a static field and a field in the row

[StevenScharf]

I have a spreadsheet with 500 plus rows. Column J is enrollment #s. Column M needs to be =Sum(J14:M13). Cell M13 is an amount that can and will change, so I can not make it a hard number.

Ie.:

=Sum(J14*m13)
=Sum(J15*m13)
=Sum(J16*m13)
=Sum(J17*m13)
=Sum(J18*m13)
=Sum(J19*m13)

If I try to populate by copy/paste or clicking on the bottom corner, it gives me this.

=Sum(J14*m13)
=Sum(J15*m14)
=Sum(J16*m15)
=Sum(J17*m16)
=Sum(J18*m17)
=Sum(J19*m18)

How do I get the first set?

[karolus]

Please, please, please avoid this useless use of SUM!
Start with:

=J14*M$13

and pull down

[robleyd]

@StevenScharf may also wish to refer to Addresses and References, Absolute and Relative

[StevenScharf]

Thank you this solved the issue.