Long (column) addition
Stacking numbers vertically, lining up place value, adding column by column with carrying.
Column addition is taught in Year 3 with two-digit numbers, extended to four digits in Year 4 and decimals/larger in Years 5-6. The trick is lining up the columns so ones meet ones, tens meet tens.
Worked examples
248 + 367 = 615. 8+7=15 (write 5, carry 1); 4+6+1=11 (write 1, carry 1); 2+3+1=6.
Decimals: 12.4 + 5.78 = 18.18. Line up the decimal point, add zero placeholder if needed.
Five 4-digit numbers stack the same way — just more rows.
Frequently asked questions
What if I forget to carry?
Common Year 3 mistake. Practise saying ‘15 is one ten and 5 ones’ out loud as you write.
Decimals trip me up — how do I align?
Line up the decimal point first, even if it means adding zeros (e.g. 12.40 + 5.78). Don't right-align the digits as for whole numbers.