### Planning and Activities

**Day 1 Teaching**

Discuss what strategies we can use to add two 2-digit numbers, and then how we can use those same strategies to add a 2-digit number to a 3-digit number. Use the same strategies to add pairs of 3-digit numbers where a mental strategy would be quicker than column addition.

**Group Activities: T with Y3**

Use the ‘Make 100’ in-depth problem-solving investigation below as today’s group activity.

Or, use these activities:

Y3 -- Use spinners to generate 2-digit numbers to add. Children discuss which strategy they used each time.

Y4 -- Decide when additions can be efficiently solved using a mental strategy rather than column addition. Some children will find trios with a total of 100, then 200.

**Day 2 Teaching**

Children subtract 20p, then 21p and 19p from prices.

**Further Teaching with Y4**

Use Frog to find out how much further cyclists need to cycle from 625 to 874 miles. Sketch a bar model to represent this.**Group Activities: T with Y4**

Y3 -- Reduce prices by near multiples of 10p; Reduce prices by 32p and 29p.

Y4 -- Use counting up to find the difference between two 3-digit numbers.

**Day 3 Teaching**

Show children items with prices tags less than £5 and a £5 note. Together calculate the change using Frog. Repeat, finding the change from £10.**Further Teaching with Y3**

Revise using Frog to subtract pairs of 2-digit numbers.

**Group Activities: T with Y3**

Y3 -- Frog investigation: think of a 2-digit number, 1st digit greater than 2nd, reverse and subtract, e.g. 85 – 58.

Y4 -- Count up to find change from £5 and £10.

**Day 4 Teaching**

Discuss choosing Frog or counting back to subtract 2-digit numbers. Begin to recognise what it is about the numbers that informs this choice.**Further Teaching with Y4**

Show a table of items with their ‘old’ and ‘sale’ prices. Demonstrate how to use Frog to count up to find the difference between each pair of prices.**Group Activities: T with Y4**

Y3 -- Choose Frog or counting back to subtract; explain choices.

Y4 -- Count up to find the difference between two amounts of money; use addition to check answers to subtractions.