Solution: It is known that the coal consumption this year is 120 tons, and it is planned to use 105 tons next year.
The planned coal saving is120-105 =15 tons.
Then the percentage saved compared with this year is15 ÷120 x100% =12.5%.
That is, it is planned to deposit 15% next year.
Multiplication operation property
Multiply the product of several numbers by a number so that any factor in the product can be multiplied by this number and then multiplied by other numbers. For example: (25×3 × 9)×4=25×4×3×9=2700.
Multiply a number by the difference between two numbers, and you can multiply the minuend and the minuend by this number respectively, and then subtract the product.
Refer to the above content: Baidu Encyclopedia-Four Arithmetic