disp('Welcome to multiplication game!')
disp('(Empty to quit)')

s = 'start';
while numel(s)>0
    a = randi([0, 9]);
    b = randi([0, 9]);
    s = input([num2str(a),'*',num2str(b),'='],'s');
    p = str2num(s);    
    if isempty(p) && ~isempty(s)
        disp("I don't understand that.")
    elseif p == a*b
        disp('Good job!')
    else
        disp('Oh, no, try again.')
    end
end