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Column subtraction 4: Lesson 3: walruses

3 - Whiteboard Challenges

Spot the Mistake!

Someone has made a mistake in their column subtraction. Can you explain the mistake to your talk partner?

Did you know?

Walruses have few natural predators, although polar bears and killer whales are known to occasionally attack them. However, even an injured walrus is a formidable opponent for a polar bear, and direct attacks are rare.

Use PAWS, counters and column subtraction to solve the following word problem.

A brave polar bear charged at a colony of 2,604 basking female walruses. During the attack, 1,316 walruses retreated to the relative safety of the water, while the remaining walruses stayed on land and formed a barrier of blubber around their calves.

How many walruses remained on land in the polar bear attack?