# Number (multiplication and division): Mud Nets

## Challenge level ⭐

(designed for children with prior knowledge of the Year 3 programme of study)

Learning Objective

We are learning how to solve a natural world problem by using and applying our skills and knowledge of number, addition and multiplication.

Useful prior knowledge:

• Doubling one-digit and 2-digit numbers
• To add and subtract two 2-digit numbers

Credit: BBC One - Life

## Clip Description

Bottle-nose dolphins are one of the most intelligent animals on earth. They can be spotted in bays and river esturies around the UK, gliding through the water and playing. This magnificent mammal usually finds its food through a process called echolocation. This involves making a series of high-pitched clicks (up to 1,000 clicks per second) that bounce off prey to reveal its size, shape and location to the dolphin.

In this fascinating clip, a pod of bottle-nose dolphins have developed a different method for hunting prey. They create perfect circles of mud from the sea floor, which they stir up with their tails. The circles of mud act like nets, trapping any fish inside. What do you think will happen to the fish that try to escape the mud by jumping up and over it? Watch the clip to find out.

## Quick Whiteboard Challenge

Dolphins can dive as deep as 250 m below the surface of the water and hold their breaths for up to 7 minutes. How many number sentences can you write that equal 250?

e.g.  100 + 100 + 50 = 250      25 x 10 = 250