Well this is a very fun thing to do and will give you so much logical understanding that it can even become a burden in every day life
There are actually a lot of ways to draw a Venn Diagram but there is a sort of a standard way that works for two sets or three sets
You could do this by getting a piece of paper
Near the middle, mark 3 points in a triangle about 2 inches apart
Then draw a circle around each point that has radius 3
Then draw a rectangle around the whole thing.
U
--------------------------
| ______ _____ |
| C / \/ \ G |
| / /\ II \ |
| | I |__|__ | |
| | /| V| \ | |
| \ | \ |VII| | |
| \ | IV / | / |
| \__|___/ \__|/ |
| | III | |
| \______/ VIII|
| P |
--------------------------
The three circles separate the rectangle into 8 areas
which I labeled with roman numerals. The number VI (six) is missing
because it would not fit in its place between I and II.
The three circles are labeled C for child, G for grandparent, and P for poet.
The eight areas can be understood like this:
I: Houses with a Child but no Grandparent or Poet
II: Houses with a Grandparent but no Child or Poet
III: Houses with a Poet but no Grandparent or Child
IV: Houses with a Child and a Poet but no Grandparent
V: Houses with a Child, a Grandmother, and a Poet
VI: Houses with a Child and a Grandmother but no Poet
VII: Houses with a Grandmother and a Poet but no Child
VIII: Houses with no Child, no Grandparent, and no Poet
You can put the numbers in the areas to show how many kind of each house there is. I see in your numbers VIII has zero, V has 1, C has 800 total, G has 250 total, P has 60 total.
Some of your numbers I am not sure if I understand exactly because if you say Children and Grandmothers - 100 then this could mean different things:
1) There are 100 houses that have a grandmother and a child, and maybe a poet or maybe not a poet. This would be VI (which I didn't label)
2) There are 100 houses that have a grandmother and a child, but definitely not a poet. This would be VI + V.
(I warn you not to do like me and alienate yourself from your friends and colleagues by constantly asking them which of these two things they mean whenever they try to use the word 'and'.)
There are some equations you can use in solving problems that have to do with diagrams like this
1. C = I + IV + V + VI
2. G = II + V + VI + VII
3. P = III + IV + V + VII
4. U = I + II + III + IV + V + VI + VII + VIII
There is more that can be said about these diagrams especially if set intersection symbol and union symbol is used. I am not sure how to make that come up yet! Sorry!
Good luck & I hope this explains it some