4 with 1
Number 1 is usually incompatible with number 4, this combination can't reach a mutual decision about anything. The combination is totally incompatible when it comes to business or love partnerships.

4 with 2
This is a combination that seems to offer a lot emotionally, but 2 has a tendency to get bored with 4's consistent routines. They can be a successful duo when it comes to business and love.

4 with 3
Even though prosperity eludes this combination it is an okay combination for family life. In family and love matters, they will compensate each other's shortcomings. 

4 with 4
When these numbers come together, their relationship may become excellent or extremely stressful. They have a tendency to get irritated quickly when their daily routines are disturbed. It is considered to be a good match in both love and business.

4 with 5
These two numbers have different temperaments that make compatibility impossible. Quite often, the numbers have initial attraction only. This combination is not recommended for any kind of relationship especially long term ones.

4 with 6
Since both are family - oriented, these two work well as marriage partners. They have some common traits like practicality, responsibility, a strong sense of community but they have a tendency to compete with each other. Since both are not good at compromising, it will be a challenge for them. 

4 with 7
There is not much energy between these two numbers and they may have to make compromises to develop a relationship. Not recommended for any kind of relationship, this combination is often found among relationships that have started at a very early age. 

4 with 8
This is an excellent combination not only in love but also in business. Both these numbers are hard workers and together they can multiply their output. They know how to prepare for the future and develop a strong and a deep spiritual relationship. 

4 with 9
The combination of these two numbers is very different and the success of their relationship depends upon their willingness to allow each other a lot of freedom. Not recommended for any kind of interaction or relationship.