Measuring for a mitzvah - "מדידה של מצוה". Preferably should be done on "ערב שבת".
How do we understand the אסור מדרבנן (rabbinical restriction) of Memachaik;
When Is One Allowed to Blow Dirt Out of or Just to the Side of a Cup?;
Is One Allowed to Cut a Pill or a Suppository in Half When They Want a Specific Size;