We have hundreds of course questions with personalized recommendations + Account 100% premium
To solve this problem, we'll follow these steps:
Let's work through each step:
Step 1: Write the numbers in vertical alignment:
Step 2: Add the digits in the ones column (rightmost):
. Since this is more than 9, write 1 in the ones place and carry over 1 to the tens place.
Step 3: Add the digits in the tens place:
Including the carried over 1 from the ones addition, add .
Write 9 in the tens place.
Therefore, the sum of is .
Thus, the correct solution to the problem is 91.
91
\( \begin{aligned} &90 \\ +& \\ &~~9\\ &\underline{\phantom{776}} & \\ \end{aligned} \)
When you add digits and get a number greater than 9, you write the ones digit in that column and carry the tens digit to the next column. For example, 2+9=11, so write 1 and carry 1.
We add from right to left because of place value! The rightmost column is ones, then tens, then hundreds. If you need to carry, it moves to the next higher place value.
You need to carry whenever the sum of digits in a column is 10 or greater. Since each place can only hold digits 0-9, anything 10 or more needs to be regrouped.
Your answer will be wrong! Always remember to add the carried digit to the next column. In this problem, don't forget to add the carried 1 to 5+3 in the tens place.
Yes! Try estimation: 52 is close to 50, 39 is close to 40, so 50+40=90. Since 91 is close to 90, your answer makes sense!
Line them up carefully by place value! Make sure ones digits are under ones digits, tens under tens, etc. This prevents alignment errors that lead to wrong answers.
Get unlimited access to all 18 Arithmetic Operations questions, detailed video solutions, and personalized progress tracking.
Unlimited Video Solutions
Step-by-step explanations for every problem
Progress Analytics
Track your mastery across all topics
Ad-Free Learning
Focus on math without distractions
No credit card required • Cancel anytime