The Rock Lock Hammer

Nobita got 0 points again in the test. On the way home from school, as I walked thinking about where to go for the test, Suneo came from behind. Suneo who makes a fool of Nobita's score and makes his own score.

When Nobita returns home, her mom asks her about the test, but she manages to cheat and go to her room. Then, in the middle of the room, I found a box with the words "luxury dorayaki"! Nobita unintentionally opened the lid and tried to eat, but what was inside was a round stone!

According to Doraemon, who just returned there, he locked the dorayaki with "Rock Rock Hammer" so that Nobita couldn't eat it. This hammer is a secret tool that locks important things, and when I hit the stone with the pointed side of the hammer, Dorayaki came out from inside!

Nobita, who heard that once locked, wouldn't be afraid to hit him in a tank or blow it up with dynamite, would lock the test so that his mom wouldn't find it ...! ??