You can, formta example, subtract 2X from
book ruby red sides, if there are two X-boxes on both sides. You can multiply or divide only by numbers, and only if the operation can be done in whole numbers. Thus if you have an even number of blocks and of X-boxes on both pans of the balance beam, then you can divide both sides by 2, and you might wish to ij things to both sides to allow such a division.