why “thirtyfive”?

In Exodus 35, the Israelites are instructed by God to build a tabernacle, which is a portable, tent-like structure that will serve as a place of worship and a dwelling place for God's presence. The tabernacle is to be built according to a detailed set of instructions that God gives to Moses.
Exodus 35:35 specifically says, "He [Bezalel] has filled them [the Israelites] with the Spirit of God, with wisdom, with understanding, with knowledge and with all kinds of skills— to make artistic designs for work in gold, silver and bronze, to cut and set stones, to work in wood, and to engage in all kinds of crafts." This verse describes how God has gifted the Israelites with the skills and abilities necessary to build the tabernacle.
This verse is a foundation for thirtyfive. It emphasizes the importance of cultivating and utilizing a wide range of skills and expertise in order to create something of value. 
This verse emphasizes the value of hard work and dedication in achieving success. In thirtyfive, this could translate to a commitment to consistently producing high quality work, being open to learning and improving skills, and persevering through challenges and setbacks in order to bring creative ideas to fruition.