void main()
{
	int n,i,j,k,l,m;
	char a[50][100];
	scanf("%d",&n);
	for(i=0;i<=2*n-2;i=i+2)
	{
	    scanf("%s",a[i]);
		scanf("%s",a[i+1]);
		printf("\n");
	}
	for(i=0;i<=2*n-2;i=i+2)
	{
		for(j=0;a[i][j]!='\0';j++)	
		    ;
		for(k=0;a[i+1][k]!='\0';k++)	
		    ;
		if(j>k)
		{
			for(l=j-1;l>=j-k;l=l-1)
				a[i+1][l]=a[i+1][l-j+k];
            for(l=j-k-1;l>=0;l=l-1)
				a[i+1][l]=48;
			for(l=j-1;l>=0;l=l-1)
			{
				if(a[i][l]>=a[i+1][l])a[i][l]=a[i][l]-a[i+1][l]+48;
				else 
				{
					a[i][l]=a[i][l]+10-a[i+1][l]+48;
					a[i][l-1]=a[i][l-1]-1;
				}
			}
			if(a[i][0]!=48)
			for(l=0;l<=j-1;l++)printf("%c",a[i][l]);  
			else
			{
			    for(l=0;a[i][l]==48;l++);
				for(m=0;m<=j-1-l;m++)
				{
					a[i][m]=a[i][m+l];
					printf("%c",a[i][m]);
				}
			}
			printf("\n");
		}

		if(j<k)
		{
			printf("-");
			for(l=k-1;l>=k-j;l=l-1)
				a[i][l]=a[i][l-k+j];
            for(l=k-j-1;l>=0;l=l-1)
				a[i][l]=48;
			for(l=k-1;l>=0;l=l-1)
			{
				if(a[i+1][l]>=a[i][l])a[i+1][l]=a[i+1][l]-a[i][l]+48;
				else 
				{
					a[i+1][l]=a[i+1][l]+10-a[i][l]+48;
					a[i+1][l-1]=a[i+1][l-1]-1;
				}
			}
			if(a[i+1][0]!=48)
			   for(l=0;l<=k-1;l++)printf("%c",a[i+1][l]);
			else
			{
			    for(l=0;a[i+1][l]==48;l++);
				for(m=0;m<=k-1-l;m++)
				{
					a[i+1][m]=a[i+1][m+l];
					printf("%c",a[i+1][m]);
				}
			}
			printf("\n");
		}
		if(j==k)                             
		{
			for(l=0;l<=j-1;l++)
				if(a[i][l]-a[i+1][l]!=0)break;
			if(l==j)printf("0");
			else
			{
			    for(l=j;l>=1;l=l-1)
				    a[i][l]=a[i][l-1];
			    a[i][0]=49;
			    for(l=j;l>=1;l=l-1)
			    	a[i+1][l]=a[i+1][l-1];
			    a[i+1][0]=48;
			    for(l=j;l>=0;l=l-1)
				{
			    	if(a[i][l]>=a[i+1][l])a[i][l]=a[i][l]-a[i+1][l]+48;
			    	else 
					{
				    	a[i][l]=a[i][l]+10-a[i+1][l]+48;
				    	a[i][l-1]=a[i][l-1]-1;
					}
				}
		    	if(a[i][0]==49)
				{
		        	if(a[i][1]!=48)
				    for(l=1;l<=j;l++)printf("%c",a[i][l]);
				    else
					{
				         for(l=1;a[i][l]==48;l++);
			    	    for(m=0;m<=j-l;m++)
						{
					        a[i][m]=a[i][m+l];
					        printf("%c",a[i][m]);
						}
					}
				}
		    	else
				{
					a[i+1][0]=49;
			    	for(l=1;l<=j;l++)
				        a[i+1][l]=48;
					for(l=j;l>=1;l=l-1)
					{
				        if(a[i+1][l]>=a[i][l])a[i+1][l]=a[i+1][l]-a[i][l]+48;
				        else 
						{
					        a[i+1][l]=a[i+1][l]+10-a[i][l]+48;
					        a[i+1][l-1]=a[i+1][l-1]-1;
						}
					}
					printf("-");
					for(l=0;a[i+1][l]!=48;l++);
					for(k=l+1;k<=j;k++)printf("%c",a[i+1][k]);
				}
			} 
			printf("\n");
		}
	}	
}