# Video: Solving Word Problem Involving Subtraction of Numbers up to 999

Students want to plant 621 trees in their village. They have planted 476 trees. How many are left?

02:56

### Video Transcript

Students want to plant 621 trees in their village. They have planted 476 trees. How many are left?

When we’re solving word problems, we always begin by highlighting the key numbers and phrases. Students want to plant 621 trees. They have already planted 476. So we need to calculate how many trees they still have left to plant.

Now we have our key words and numbers, we can record our equation. Students had 621 trees to begin with. They planted 476. Did the students add 476 trees or take them away? That’s right! They took them away. They took them away to plant them.

The correct operation to use is minus, 621 minus 476. This will tell us how many trees are left to plant. Now what we need to do is calculate the answer using column subtraction, 621 minus 476.

We start in the ones column. And we need to calculate one minus six. The bottom number six is greater than one. So we’re gonna have to take a 10 from the tens column. We’ve taken a 10 from the tens column and placed it in the ones column. Now we can calculate 11 minus six, which is five.

Next, we move into the tens place. We need to calculate one minus seven. Again, the bottom number is greater than the top number. So we need to regroup. We’ve taken one from the hundreds column and we’ve added it to the tens column. So now we can calculate 11 minus seven, which is four.

Now we can move into the hundreds column. And we need to calculate five minus four, which is one. 621 minus 476 equals 145. Students had 621 trees. They planted 476. They still have 145 trees left to plant. We calculated our answer using column subtraction.