Multiplying Columns using a WITH clause

Hello all Im trying to Find the total value of an order Through Arthmetic(Quanity * Unit_price) which i can do BUT the question wants me to do so using a nest query and a WITH clause. How would I implement the WITH clause?

below is what ive done but not meeting the procedure requirements

SELECT ORDER_ID
FROM ORDERS
WHERE ORDER_ID IN
(SELECT(QUANTITY * UNIT_PRICE) AS TOTAL_VALUE
FROM ORDER_DETAIL)
ODER BY ORDER_ID ASC;

CREATE TABLE ORDERS
(
    ORDER_ID        DECIMAL(9)  NOT NULL,
    CUSTOMER_CODE   VARCHAR(5)  NOT NULL,
    EMPLOYEE_ID     DECIMAL(9)  NOT NULL,
    ORDER_DATE      DATE        NOT NULL,
    REQUIRED_DATE   DATE,
    SHIPPED_DATE    DATE,
    SHIP_VIA        VARCHAR(40),
    FREIGHT         DECIMAL(10,2)           DEFAULT 0,
    SHIP_NAME       VARCHAR(40),
    SHIP_ADDRESS    VARCHAR(60),
    SHIP_CITY       VARCHAR(15),
    SHIP_REGION     VARCHAR(15),
    SHIP_POSTAL_CODE    VARCHAR(10),
    SHIP_COUNTRY    VARCHAR(15),
    CONSTRAINT PK_ORDERS PRIMARY KEY (ORDER_ID),
    CONSTRAINT FK_CUSTOMER_CODE FOREIGN KEY (CUSTOMER_CODE) REFERENCES CUSTOMER(CUSTOMER_CODE),  
    CONSTRAINT FK_EMPLOYEE_ID FOREIGN KEY (EMPLOYEE_ID) REFERENCES EMPLOYEE(EMPLOYEE_ID),  
    CONSTRAINT FK_SHIP_VIA FOREIGN KEY (SHIP_VIA) REFERENCES SHIPPER(COMPANY_NAME)  
);

CREATE TABLE ORDER_DETAIL
(
    ORDER_ID         DECIMAL(9) NOT NULL,
    PRODUCT_NAME     VARCHAR(40)    NOT NULL,
    UNIT_PRICE       DECIMAL(10,2)  NOT NULL    DEFAULT 0,
    QUANTITY         DECIMAL(9) NOT NULL    DEFAULT 1 ,
    DISCOUNT         DECIMAL(4,2)   NOT NULL    DEFAULT 0,
    CONSTRAINT PK_ORDER_DETAIL PRIMARY KEY (ORDER_ID, PRODUCT_NAME),
    CONSTRAINT FK_ORDER_ID FOREIGN KEY (ORDER_ID) REFERENCES ORDERS (ORDER_ID),
    CONSTRAINT FK_PRODUCT_NAME FOREIGN KEY (PRODUCT_NAME) REFERENCES PRODUCT (PRODUCT_NAME),
    CONSTRAINT CK_ORDER_DETAIL_UNIT_PRICE CHECK (UNIT_PRICE >= 0),
    CONSTRAINT CK_ORDER_DETAIL_QUANTITY CHECK (QUANTITY > 0),
    CONSTRAINT CK_ORDER_DETAIL_DISCOUNT CHECK (DISCOUNT between 0 and 1)
);

i think i might need to use this table but i am unsure(TABLE PRODUCT)

CREATE TABLE PRODUCT
(
    PRODUCT_NAME    VARCHAR(40)     NOT NULL,
    SUPPLIER_NAME   VARCHAR(40)     NOT NULL,
    CATEGORY_NAME   VARCHAR(30) NOT NULL,
    QUANTITY_PER_UNIT   VARCHAR(20),
    UNIT_PRICE      DECIMAL(10,2)   NOT NULL    DEFAULT 0,
    UNITS_IN_STOCK  DECIMAL(9)  NOT NULL    DEFAULT 0,
    UNITS_ON_ORDER  DECIMAL(9)  NOT NULL    DEFAULT 0, 
    REORDER_LEVEL   DECIMAL(9)  NOT NULL    DEFAULT 0,
    DISCONTINUED    CHAR(1)     NOT NULL    DEFAULT 'N',
    CONSTRAINT PK_PRODUCT PRIMARY KEY (PRODUCT_NAME),
    CONSTRAINT FK_CATEGORY_NAME FOREIGN KEY (CATEGORY_NAME) REFERENCES CATEGORY(CATEGORY_NAME),
    CONSTRAINT FK_SUPPLIER_NAME FOREIGN KEY (SUPPLIER_NAME) REFERENCES SUPPLIER(COMPANY_NAME),
    CONSTRAINT CK_PRODUCT_UNIT_PRICE CHECK (UNIT_PRICE >= 0),
    CONSTRAINT CK_PRODUCT_UNITS_IN_STOCK CHECK (UNITS_IN_STOCK >= 0),
    CONSTRAINT CK_PRODUCT_UNITS_ON_ORDER CHECK (UNITS_ON_ORDER >= 0),
    CONSTRAINT CK_PRODUCT_REORDER_LEVEL CHECK (REORDER_LEVEL >= 0),
    CONSTRAINT CK_PRODUCT_DISCONTINUED CHECK (DISCONTINUED in ('Y','N'))
);

This is the exact question

“A total value of an order must be computed as the summation of unit price * quantityover all items included in the order. The query must be implemented as a sequence of subquery definitions following WITH keyword and ended with the final SELECT.

(i) The first subquery definition must find a total value of each order together with an order identifier (attribute order_id). “

im currently on (i)

Multiplying Columns using a WITH clause