Greg has 60 building blocks. His sister gives him 17 more blocks. He uses 38 blocks to make a tower. How many blacks are not used in the tower?
The correct answer and explanation is:
Let’s break down the problem step by step:
Problem:
- Greg initially has 60 building blocks.
- His sister gives him 17 more blocks.
- He uses 38 blocks to build a tower.
- Question: How many blocks are left unused (not used in the tower)?
Step 1: Find the total number of blocks Greg has now
Greg originally has 60 blocks.
His sister gives him 17 more.
Total blocks Greg has:
60+17=7760 + 17 = 77
Step 2: Determine how many blocks are not used
Greg uses 38 blocks to make the tower.
The unused blocks = Total blocks – Blocks used in the tower
77−38=3977 – 38 = 39
Answer:
39 blocks are not used in the tower.
Explanation (300 words):
This problem involves basic addition and subtraction, and it helps to clearly understand what is being asked. First, we find the total number of blocks Greg has after receiving more from his sister. Initially, Greg has 60 blocks. When his sister gives him 17 more, you simply add these two amounts together to get the new total of blocks.
Once the total number of blocks is known, the next step is to identify how many blocks Greg uses to build the tower. The problem states that he uses 38 blocks for this purpose. To find out how many blocks are left unused, we subtract the number of blocks used from the total number of blocks he owns.
This subtraction step gives us the remaining blocks, which are blocks that Greg did not use in building the tower. The result, 39 blocks, tells us how many blocks remain free and could be used for other things or saved.
Understanding this kind of problem is useful because it demonstrates how to combine addition and subtraction in a real-life context, which is a fundamental skill in mathematics. It shows the relationship between parts of a whole and how quantities change with additions and subtractions.
Additionally, problems like this reinforce the importance of reading carefully to know exactly what is being asked — in this case, the number of blocks not used. It’s an excellent example for beginners learning to work with basic arithmetic operations and to think logically through a problem step by step.