### Teaching and Group Activities for Understanding

**Day 1 Teaching**

Write 4.735 and ask children what the 7, 3 and 5 represent. Agree they are tenths, hundredths, thousandths. Show this on a place value grid. After subtracting 0.005, check that they write 4.73 not 4.730. Emphasize that we only write 0 in thousandths place if there are digits after this. Children add and subtract multiples of 0.1, 0.01 and 0.001.**Group Activities**

Use the in-depth problem-solving investigation ‘The Size and Distance of the Planets’ from UC Berkeley as today’s group activity.

Or, use these activities:

-- Add and subtract 0.1s. 0.01s and 0.001s, using a calculator to test predictions.

-- Add and subtract 0.1s. 0.01s and 0.001s from 3.457 to make target numbers.

**Day 2 Teaching**

Launch the ITP ‘Moving digits’. Use the cards to show 56. Click to multiply by 10 three times, saying multiply by 10, 100, 1000. Discuss how much we have multiplied by and what the effect on the digits is. Discuss the effect of dividing 2340 by 1000. Then multiply and divide other numbers by 10, 100 and 1000, monitoring the effect on the digits.

**Group Activities**

-- Sequentially multiply and divide a number by powers of 10 to arrive back at the starting number.

-- Divide four numbers by 100 and 1000, then order. Repeat for multiplying by 100 and 1000.

**Day 3 Teaching**

Show children a counting stick for 2–3. Count from 2 to 3 in steps of 0.1. Children draw a line 2.3–2.4 and mark a number with 2 decimal places. What does this round to? Repeat, for numbers with 3 decimal places.

**Group Activities**

-- Round numbers with 3 decimal places to the nearest whole kilogram.

-- Generate, then round numbers with 3 decimal places to the nearest whole, tenth and hundredth.