Main Idea and Key Details is a free printable Grade 3 English worksheet on matching a main idea to the key detail that supports it, aligned to Common Core standard RI.3.2. It prints 3 questions with an answer key on its own sheet of paper, in 25 versions that each ask different questions, so no two students in the class work from the same page. Print it from the browser or download it as a PDF — no account, no email.
Set 7 of 25 · the same problems every time you open this link.
Set 1 has all 25 in a single PDF. All 25 sets ask different questions.
Main Idea and Key Details
RI.3.2
NameDate
Write the letter of the detail next to each main idea.
1.Write the letter of the key detail that supports each main idea.
Beavers change rivers by building dams.
Bees work together to run the hive.
Louis Braille invented a way for blind people to read.
Cheese is made by separating the protein in milk.
A.He used a cell of six raised dots.
B.Rennet splits the milk into curds and whey.
C.Some bees collect nectar while others guard the door.
D.They pile up sticks and mud until the water backs up.
2.Write the letter of the key detail that supports each main idea.
A salmon returns to the river where it hatched.
Morse code turns letters into short and long signals.
Lighthouses keep ships away from rocks.
Frogs change shape as they grow.
A.A tadpole grows back legs before front legs.
B.Their lamps flash a pattern sailors can see at night.
C.E is one dot and T is one dash.
D.It finds the river by its smell.
3.Write the letter of the key detail that supports each main idea.
A windmill turns moving air into turning stone.
Yeast makes bread rise.
Swallows leave Britain to follow their food.
Trees help keep soil in place.
A.It gives off gas that is trapped in the dough.
B.The sails turn a shaft that turns the millstone.
C.Flying insects disappear in October.
D.Their roots hold the earth together in heavy rain.
LessonPrint · RI.3.2 · Set 7 · free to copy for classroom use
Answer key — Main Idea and Key Details
Set 7. Prints on its own sheet.
1.1. Beavers change rivers by building dams. — D (They pile up sticks and mud until the water backs up.) 2. Bees work together to run the hive. — C (Some bees collect nectar while others guard the door.) 3. Louis Braille invented a way for blind people to read. — A (He used a cell of six raised dots.) 4. Cheese is made by separating the protein in milk. — B (Rennet splits the milk into curds and whey.)
2.1. A salmon returns to the river where it hatched. — D (It finds the river by its smell.) 2. Morse code turns letters into short and long signals. — C (E is one dot and T is one dash.) 3. Lighthouses keep ships away from rocks. — B (Their lamps flash a pattern sailors can see at night.) 4. Frogs change shape as they grow. — A (A tadpole grows back legs before front legs.)
3.1. A windmill turns moving air into turning stone. — B (The sails turn a shaft that turns the millstone.) 2. Yeast makes bread rise. — A (It gives off gas that is trapped in the dough.) 3. Swallows leave Britain to follow their food. — C (Flying insects disappear in October.) 4. Trees help keep soil in place. — D (Their roots hold the earth together in heavy rain.)
More practice for RI.3.2
State the main idea and show which details hold it up.