NSString *tempA = @"123";
NSString *tempB = @"456";

NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];

int intString = [newString intValue];

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];

float floatString = [newString floatValue];

NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];