Solve the Division Problem: 90÷5 Step-by-Step

Q: Why split 90 into 50 + 40 instead of other combinations?

Because both 50 and 40 are multiples of 5! This makes the division easier: 50÷5 = 10 and 40÷5 = 8. You could use other splits, but this one gives the simplest mental math.

Q: Does the distributive property always work for division?

Yes! The formula $ (a+b)÷c = a÷c + b÷c $ always works. You can also use subtraction: $ (a-b)÷c = a÷c - b÷c $.

Q: What if I can't think of good numbers to split with?

Look for multiples of your divisor! For 90÷5, think of numbers that end in 0 or 5. Try: 45+45, 60+30, or 80+10. All work perfectly!

Q: Is it okay to just memorize that 90÷5 = 18?

Memorizing helps with speed, but understanding the method helps you solve any division problem! The distributive property works for much harder problems too.

Q: How do I check if 18 is really the right answer?

Multiply backwards: 18 × 5 = 90. Since multiplication and division are opposite operations, this confirms your answer is correct!

Step-by-step video solution

Watch the teacher solve the problem with clear explanations

00:00 Solve

00:03 We'll use the distributive law

00:07 Let's break down 90 into 20, 20, and 50

00:18 We'll divide each factor separately

00:36 We'll solve each division and then sum

00:47 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution

1

Understand the problem

Solve the following exercise

=90:5

2

Step-by-step solution

We use the distributive property of division to separate the number 90 between the sum of 50 and 40, which facilitates the division and gives us the possibility to solve the exercise without a calculator.

Keep in mind: it is beneficial to choose to split the number according to your knowledge of multiples. In this case into multiples of 5, because it is necessary to divide by 5.

Reminder: the distributive property of division actually allows us to separate the larger term in a division exercise into the sum or the difference of smaller numbers, which facilitates the division operation and gives us the possibility to solve the exercise without a using calculator.

We use the formula of the distributive property

$(a+b):c=a:c+b:c$

$90:5=(50+40):5$

$(50+40):5=50:5+40:5$

$50:5+40:5=10+8$

$10+8=18$

Therefore, the answer is option c: 18

3

Final Answer

18

Key Points to Remember

Essential concepts to master this topic

Distributive Property: Break apart numbers into easier multiples for division
Split Strategy: 90 = 50 + 40, both divisible by 5
Verify: Check that 18 × 5 = 90 to confirm answer ✓

Common Mistakes

Avoid these frequent errors

Dividing without considering easier number combinations
Don't just try 90÷5 directly if you struggle with mental math = confusion and wrong answers! This makes simple division unnecessarily difficult. Always look for ways to break numbers into multiples of your divisor first.

Practice Quiz

Test your knowledge with interactive questions

$$ 140-70= $$

FAQ

Everything you need to know about this question

Why split 90 into 50 + 40 instead of other combinations?

+

Because both 50 and 40 are multiples of 5! This makes the division easier: 50÷5 = 10 and 40÷5 = 8. You could use other splits, but this one gives the simplest mental math.

Does the distributive property always work for division?

+

Yes! The formula $(a+b)÷c = a÷c + b÷c$ always works. You can also use subtraction: $(a-b)÷c = a÷c - b÷c$ .

What if I can't think of good numbers to split with?

+

Look for multiples of your divisor! For 90÷5, think of numbers that end in 0 or 5. Try: 45+45, 60+30, or 80+10. All work perfectly!

Is it okay to just memorize that 90÷5 = 18?

+

Memorizing helps with speed, but understanding the method helps you solve any division problem! The distributive property works for much harder problems too.

How do I check if 18 is really the right answer?

+

Multiply backwards: 18 × 5 = 90. Since multiplication and division are opposite operations, this confirms your answer is correct!

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Solve the Division Problem: 90÷5 Step-by-Step

Division Strategy with Distributive Property

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