Chapter 9.7, Problem 2OE

To determine

To express: the value of the two-digit number in terms of t and u .

Answer to Problem 2OE

The value of 2-digit number by reversing digits is $10u+t$ .

Explanation of Solution

Given information:

A two-digit number has tens digit t and units digit u .

Reverse the digits.

Formula used:

Digit problems are based on our decimal system of numeration.

Step1. The problem asks for the original number.

Step2. Let t = the tens digit of the original number.

Let u = the units digit of the original number.

Step3. Use the facts of the problem to write two equations.

Step4. Solve the equations.

Calculation:

Consider ,

Let t = the tens digit of the original number.

Let u = the units digit of the original number.

	Tens	Units	Value
Original number	t	u	$10t+u$
Number with digit reversed	u	t	$10u+t$

Hence, the value of 2-digit by reversing number is $10u+t$ .