Please, can you provide some screenshot ?

I test with a non admin user and it's OK (With edit HTML source)

1 & lt ; 2 {1 < 2}<br />
1 & lt ;= 1 {1 <= 1}

Yes, confirmed : it's the HTML editor : replace < by < before validation.

Edit source or deactiva HTML editor or use lt and not <

PS EM show error & lt ;
PS2 : can you confirm it's an HTML editor issue (and update the title if yes)

See http://manual.limesurvey.org/Expression_Manager#HTML_editor_issue

Documentation issue : affect HTML editor only.