C :

#include<stdio.h>
int gcd(int m,int n)
{
	if(m%n)
		return gcd(n,m%n);
	return n;
}
int main()
{
	int n,gbs,t,a;
	scanf("%d",&n);
	while(n--)
	{
		gbs=1;
		scanf("%d",&t);
		while(t--)
		{
			scanf("%d",&a);
			gbs=gbs*(a/gcd(gbs,a));
		}
		printf("%d\n",gbs);
	}
}

C++ :

#include<stdio.h>

long long gcd(long long x,long long y)
{
	if(!x||!y)
		return x>y?x:y;
	for(long long t;t=x%y;x=y,y=t);
	return y;
}

int main()
{
	int n,m;
	long long a,b,g,l;
	scanf("%d",&n);
	while(n--)
	{
		scanf("%d%lld",&m,&a);
		if(m==1)
		{
			printf("%lld\n",a);
			continue;
		}
		scanf("%lld",&b);
		g=gcd(a,b);
		l=a*b/g;
		m-=2;
		while(m--)
		{
			scanf("%lld",&a);
			g=gcd(a,l);
			l=a*l/g;
		}
		printf("%lld\n",l);
	}
	return 0;
}