Solve 20×1×8: Step-by-Step Multiplication Practice

Multiplication Order with Identity Property

20×1×8= 20\times1\times8= ?

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Step-by-step video solution

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00:00 Solve the following expression
00:02 Let's solve the expression according to the correct order of operations, from left to right
00:05 This is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

20×1×8= 20\times1\times8= ?

2

Step-by-step solution

According to the order of operations, we solve the exercise from left to right since there is only multiplication in the exercise:

20×1=20 20\times1=20

20×8=160 20\times8=160

3

Final Answer

160 160

Key Points to Remember

Essential concepts to master this topic
  • Order of Operations: Multiply from left to right when only multiplication present
  • Identity Property: Any number times 1 equals itself: 20×1=20 20 \times 1 = 20
  • Verification: Check by computing 20×8=160 20 \times 8 = 160 matches final answer ✓

Common Mistakes

Avoid these frequent errors
  • Adding instead of multiplying when seeing 1
    Don't think 20 × 1 × 8 = 20 + 1 + 8 = 29! Seeing the number 1 doesn't mean switch to addition - it's still multiplication. Always multiply every number in the sequence, remembering that any number times 1 stays the same.

Practice Quiz

Test your knowledge with interactive questions

Solve the following exercise:

\( 12+3\cdot0= \)

FAQ

Everything you need to know about this question

Why doesn't multiplying by 1 change the number?

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The number 1 is called the multiplicative identity because it leaves any number unchanged when multiplied. Think of it as taking 1 group of 20, which is still just 20!

Do I have to solve from left to right?

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Yes! When you only have multiplication (or only division), always work from left to right. This is part of the order of operations rules.

What if I multiplied 1 × 8 first instead?

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You'd get 1×8=8 1 \times 8 = 8 , then 20×8=160 20 \times 8 = 160 - the same answer! Multiplication is commutative, but it's still best practice to work left to right.

How do I remember that 20 × 8 = 160?

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Break it down: 20×8=2×10×8=2×8×10=16×10=160 20 \times 8 = 2 \times 10 \times 8 = 2 \times 8 \times 10 = 16 \times 10 = 160 . Or think: 20 eights is twice as much as 10 eights (80), so 2 × 80 = 160.

Why are there wrong answers like 28 and 161?

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These trap answers test common mistakes: 28 comes from adding (20+1+8), and 161 comes from calculating correctly but adding 1 at the end by accident.

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