What to notice
Every starting number is in the 3s, 4s and 6s as well, because 12 is 3 × 4 and 2 × 6. So one route to a 12s fact is to divide by 2 and then by 6: 72 ÷ 2 = 36, and 36 ÷ 6 = 6, so 72 ÷ 12 = 6.
The starting numbers go up by 12: 12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144. Several are landmarks already: 24 is the hours in a day, 60 is the minutes in an hour, and 144 is 12 × 12, the last square on the chart.
Checking a guess by multiplying is a good habit here. Because 12 is 10 + 2, 12 × 8 is 80 and 16, which is 96, so 96 ÷ 12 = 8.
Twelve is a good table for checking by estimating: 108 ÷ 12 must be a bit less than 108 ÷ 10, which is just over 10, so 9 is believable and 90 or 19 is not.
How to practise at home
- Use months: “48 months is how many years?” is 48 ÷ 12.
- Use egg cartons: lay out eggs in rows of 12 and count the rows.
- Use a ruler for inches and feet: 36 inches is 3 feet, so 36 ÷ 12 = 3.
- Use the drill on this page, and practise any slow fact as multiplication first.
- Use the clock face, with its 12 hours. “How many full turns of the hour hand in 36 hours?” is 36 ÷ 12 = 3, and a toy clock lets your child count the turns.
Slips to watch for
- Dividing by 10 and by 2 separately and adding the answers. Splitting the number you divide by does not work the way splitting a factor does; divide by 2 and then by 6 instead.
- Mixing up 96 ÷ 12 and 108 ÷ 12, whose answers are 8 and 9.
- Answering 0 or 12 for 12 ÷ 12. A number divided by itself is 1.
- Reading the fact backwards. 12 ÷ 3 = 4, but 3 ÷ 12 is a fraction, a quarter. Children who know the 3s sometimes swap the numbers; ask which number is being shared.