The planned water tonnage is "1", and the planned water tonnage multiplied by 15% is the water-saving tonnage.

The actual water consumption tonnage is (1+ 15%) of the planned water consumption, and the planned water consumption tonnage multiplied by (1+ 15%) is the actual water consumption tonnage.

Solution: Solution: If the planned water tonnage is regarded as the unit "1", then:

Planned tonnage of water × 15%= tonnage of water saving.

Planned tonnage of water × (1+ 15%) = actual tonnage of water.

So the answer is: planned water tonnage and water-saving tonnage; Tonnage of planned water, ×( 1+ 15%).

An equation refers to an equation containing unknowns. It is an equation that represents the equal relationship between two mathematical expressions (such as two numbers, functions, quantities and operations), and the value of the unknown quantity that makes the equation hold is called "solution" or "root". The process of finding the solution of the equation is called "solving the equation".

By solving the equation, we can avoid the difficulty of reverse thinking and directly list the equations with the quantity to be solved. There are many forms of equations, such as one-dimensional linear equation, two-dimensional linear equation, one-dimensional quadratic equation and so on. , can also be combined into equations to solve multiple unknowns.