Here are two big numbers I want to add together: 4,738 + 2,569. We could try it in our heads, but these numbers are awkward. Where would you start if you had to add them on paper? Hands up: would you start with the big thousands or the little units?

Look at these worked examples. Each pair is added one column at a time, starting from the units on the right. Keep an eye on the little carry digits: notice which way they travel and when a brand-new digit appears. Count the carries in the second one, and predict the last one before we check.

Today we work through this one together on the board: 6,847 + 3,956. We will set it out, then add one column at a time from the right. Before each carry lands, call out where it has to go.

Today we work through these sums together, each one a little bigger than the last. We will set each one out, add from the units, and check the answer as a class before we move on:

• 347 + 285
• 4,738 + 2,569
• 9,876 + 1,234
• 5,000 + 4,999

What we learned today

• We line numbers up by place value, units under units, and add from the right.
• When a column makes ten or more, we carry the ten one column to the left — because ten in a column is worth just one in the column above it, the spare ten cannot stay put.
• Carries can cascade — one regroup can tip the next column over too, and sometimes a brand-new digit appears.