Hunting Guide agreed to take Greenhorn on a hunting expedition into a remote area of the Alaskan wilderness. Greenhorn orally agreed to pay Hunting Guide $1,000, for which Hunting Guide orally agreed to help Greenhorn successfully navigate the treacherous terrain in Alaska for exactly seven days, from January 14 - 21. They dictated the specifics of their agreement to Country Grocer, who had a typewriter. After Country Grocer typed the agreement, Hunting Guide and Greenhorn both signed the agreement. Country Grocer, not a typist by nature, mistyped $10 as the price Greenhorn was to pay Hunting Guide, instead of $1,000. If Greenhorn refused to pay more than $10 for the hunting expedition, in an action by Hunting Guide for the additional $990, Hunting Guide should try to establish that: