### Teaching and Group Activities for Understanding

**Day 1 Teaching**Display a place value grid and write 3-digit numbers on it. Show which digit changes if you add multiples of 10. Repeat to show which digit changes if you add multiples of 100. Repeat for 1s.

**Group Activities**

**-- Spinners: adding 1s, 10s and 100s to 3-digit numbers.**

-- Making Money: adding multiples of 1s and 10s.

**Day 2 Teaching**Use a place value grid to show which digit changes if you subtract multiples of 10. Repeat for multiples of 100 or 1.

**Group Activities**

**-- Cake cards: subtracting 1s, 10s and 100s from 3-digit numbers.**

**Day 3 Teaching**Demonstrate how to add and subtract near multiples of 10 to/from 2-digit numbers using a number line, and also a 1-100 number grid.

**Group Activities**

Use the ‘Magic 147’ in-depth problem-solving investigation below as today’s group activity.

Or, use these activities:

**-- Near Multiples Game: adding and subtracting multiples of 10 and related near multiples.**

-- Alien Attack: adding multiples of 10 and related near multiples

**Day 4 Teaching**Use an empty number line to model the hops involved in adding a near multiple of 10 to a 3-digit number: 225 + 29 is 225 hop 30 along and then back 1, etc.

**Group Activities**

**-- Hexagon Multiples Game: adding multiples of 10 and related near multiples.**

**Day 5 Teaching**Use an empty number line to model the hops involved in subtracting a near multiple of 10 from a 3-digit number. Demonstrate how we adjust the hops to subtract 51 or 49 rather than 50.

**Group Activities**

-- Hexagon Multiples Game: subtracting multiples of 10 and related near multiples.