Solving “18 Divided By What Equals 90?” A Quick Math Trick

Solving
Solving

Determining the divisor that, when 18 is divided by it, yields 90, presents an intriguing mathematical challenge. This seemingly simple problem requires a shift in perspective, moving from traditional division to understanding the relationship between dividends, divisors, and quotients. Mastering this concept strengthens fundamental arithmetic skills and lays the groundwork for more complex algebraic thinking.

Understanding the Problem

The core of this challenge lies in recognizing the inverse relationship between division and multiplication. Rather than directly dividing 18, the solution involves finding a number that, when multiplied by 90, equals 18.

Converting to Multiplication

Transforming the division problem into a multiplication problem simplifies the path to a solution. This rephrasing allows for a more straightforward approach to finding the unknown value.

Applying Algebraic Principles

Representing the unknown divisor as a variable (e.g., ‘x’) allows for the application of algebraic principles. This transforms the problem into the equation 18 / x = 90, which can then be manipulated to solve for x.

Isolating the Variable

To isolate the variable ‘x’ and determine its value, both sides of the equation must be manipulated. Multiplying both sides by ‘x’ and then dividing both sides by 90 reveals the solution.

Decimal Solutions

The solution to this problem involves a decimal value, highlighting the importance of understanding decimal operations within the context of division and multiplication.

Real-World Applications

This type of problem-solving translates to practical scenarios involving proportions, ratios, and scaling. Understanding these concepts proves beneficial in various fields, from cooking and finance to engineering and science.

Strengthening Foundational Math Skills

Working through this problem reinforces fundamental mathematical principles and enhances problem-solving abilities applicable to a wide range of situations.

Developing Mathematical Intuition

Solving problems like this cultivates mathematical intuition and strengthens the ability to approach mathematical challenges with a more flexible and adaptable mindset.

Tip 1: Rewrite the Problem

Rewrite the division problem as a multiplication problem: “What number multiplied by 90 equals 18?”

Tip 2: Use a Variable

Represent the unknown number with a variable (like ‘x’) to create an equation: 18 / x = 90.

Tip 3: Isolate the Variable

Manipulate the equation to isolate ‘x’ by multiplying both sides by ‘x’ and then dividing both sides by 90.

Tip 4: Embrace Decimals

Be prepared to work with decimal numbers, as the solution will not be a whole number.

How can I check my answer?

Multiply your answer by 90. If the result is 18, your answer is correct.

Why is this type of problem important?

It reinforces core mathematical concepts and develops problem-solving skills applicable in various practical situations.

Is there another way to solve this problem besides using algebra?

Yes, you can use the concept of reciprocal multiplication. Since dividing by a number is the same as multiplying by its reciprocal, you can find the reciprocal of 90 (1/90) and multiply it by 18.

What if I get a different answer?

Double-check your calculations, ensuring you correctly applied the principles of algebraic manipulation or reciprocal multiplication.

By understanding the inverse relationship between division and multiplication, and by employing algebraic principles or the concept of reciprocals, seemingly complex problems like this become manageable. This exercise not only provides a solution but also enhances fundamental mathematical understanding and cultivates essential problem-solving skills.