[users] .ods & .odt to non-openoffice users

[Ross & Connie Dawson]

Sir,I sent a completed excel spreadsheet & they can't open it.It is in .ods 
format.Do I need to convert it to .xls? If so then how?
Similarly,I sent a word document (in  .odt format) & the recipient can't open 
it.How do I get around this problem?
Regards,Ross Dawson.