SOLUTION: hello i'm in 4th grade grade.I'm trying to figure out how to solve this algebra problems..... 10+50=80- _____ and 90-30=20+ _____ please show me how to do this. Thank you

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Question 259801: hello i'm in 4th grade grade.I'm trying to figure out how to solve this algebra problems.....
10+50=80- _____
and 90-30=20+ _____
please show me how to do this.
Thank you
Found 3 solutions by Fombitz, Alan3354, Nieleya:
Answer by Fombitz(32388)   (Show Source):
You can put this solution on YOUR website!
Let's re-write it like this,

What number subtracted from 80 gives you 60?

.
.
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What number added to 20 gives you 60?

Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website!
10+50=80- _____
Add the 10 and 50
60 = 80 - ?
Subtract 60 from both sides
0 = 20 - ?
The missing value is 20.
--------------------------
and 90-30=20+ _____
Subtrace the 30 from 90
60 = 20 + ?
Subtract 20 from both sides
40 = ?
40 is the missing value.

Answer by Nieleya(22)   (Show Source):
You can put this solution on YOUR website!
10 + 50 = 80 - _______
Let d blank be x.. so it may looks like this
10 + 50 = 80 - x
80 -10 -50 = - x
80 - 60 = 20
20 = x
x = 20/1
x = 20
to check
10 + 50 = 80 - 20
60 = 60

90 - 30 = 20 + ______
again let d blank be x
so it looks like below
90 - 30 = 20 + x
60 = 20 + x
Move 20 to the left side and it becomes -20
60 - 20 = x
40 = x
so to check whether your ans is correct
90 - 30 = 20 + 40 (which is the x)
60 = 60
Juz remember to change the sign when you move it to the other side... + becomes minus and minuse becomes plus