Math is often considered a subject of cold fact, strict rules, mechanical logic, and you can either get it right or you can't.
I have found that none of it is true.
Not only is there usually more than one correct solution to a problem in real life, but there is a crucial emotional component in learning math. My own sons, who are strong math students, have had the math homework tantrums. I can still recall, vividly, a virtual panic attack I had as a teenager over Venn diagrams. I can not recall a single story I've heard about homework tantrums that wasn't over math. Perhaps that's because of my position, which you may be surprised to hear does not make it easier for me to help my own children.
I will be careful to speak for myself, here: when my children are upset, they can't do anything but be upset. If I tell them to bag it and I'll write a note to the teacher, they will refuse to give up. Whether I try to suggest, give a clue, or even have them copy the answer from me, it is pointless. They are upset, and I am just dad, telling them more stuff they're supposed to do. The only thing that worked for me was to have them physically move away from the homework and distract them, often with a cookie.
Watch the videos on my homepage. They are from Khan Academy. Have your child watch them, and watch them more than once. For as far back as anyone can remember, math has been a throw-away subject. It was okay to give up, because some of us are just not "a math person." We can't do that anymore, and we know that basic math skills are something everyone can learn.
At home, it is different than in school. It is the end of a long day by the time most kids begin their homework. In school, it is earlier in the day, they are in a room where everyone has the same work at the same time, and there are fewer available distractions. The expectations are different. Maybe the same work was easy then, but isn't now. That happens a lot. Maybe it was hard then, and it's even harder at home. That happens, too. Try not to get caught up in the panic yourself. It will get better in time. Keep in touch with your child's teacher, or contact me. Check out my links for the homework helpers and support from Eureka Math. We do everything we can in school to set the kids up for success, but sometimes it is just harder at home.