# Column subtraction 4: Lesson 2: brittle stars

## The Maths Bit!

In this exciting lesson, you will need to solve a range of subtraction word problems that feature brittle stars. Try using **PAWS** to arrive at the right answer!

**P ** = Picture the problem in your mind.

**A **= Annotate the word problem by highlighting the important information.

**W** = Write down the number sentence that needs to be solved.

**S** = Solve the number sentence using an efficient strategy.

**Prior learning: **Subtract a 3-digit number from a 4-digit number with one or more exchanges, including an exchange across more than one place value.

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

On the floor of Loch Carron, 4,564 brittle stars were waving their arms to catch food. Of these brittle stars, a total of 2,638 caught fragments of dead animals (detritus), which were then passed into their mouths. The remaining brittle stars caught plankton (tiny sea creatures).

**How many brittle stars on the floor of Loch Carron caught plankton?**

**Did you know? **

Plankton are tiny drifting organisms that live in the ocean. They are not strong enough to swim against ocean currents. Brittle stars catch plankton on the sticky, tube-like feet that protrude from their arms.