Addition

Add Two-Digit Numbers With Carrying

Add 47 + 38 column by column. The ones sum (7 + 8 = 15) is 10 or more, so write the 5 and carry the 1 to the tens column.

Example

Add 47 and 38 with a carry from the ones column.

highlighted = computed this step

Step 1 — Set up

Line up the addends by place value.

xxx47+38x□□\begin{array}{rrr}\phantom{x}&\phantom{x}&\phantom{x}\\&4&7\\+&3&8\\\hline\\\phantom{x}&\square&\square\end{array}
Line up 47 and 38 by placetens43ones78+47 + 38Add ones first. If they make 10 or more, carry 1 ten.

Step 2 — Ones column

Ones: 7 + 8 = 15, write 5, carry 1.

x1x47+38x□5\begin{array}{rrr}\phantom{x}&\hl{1}&\phantom{x}\\&4&7\\+&3&8\\\hline\\\phantom{x}&\square&\hl{5}\end{array}
Ones: 7 + 8 = 15tens143ones785+carry 1 ten10 ones+ 5 ones7 + 8 = 15: write 5, carry 115 ones regroup as 1 ten and 5 ones.

Step 3 — Tens column

Tens: 4 + 3 + carry 1 = 8, write 8.

x1x47+38x85\begin{array}{rrr}\phantom{x}&1&\phantom{x}\\&4&7\\+&3&8\\\hline\\\phantom{x}&\hl{8}&5\end{array}
Tens: 4 + 3 + carry 1 = 8tens1438ones78+carry 1 ten10 ones+ 5 ones4 + 3 + 1 = 8 tensAdd the carried 1 ten with 4 tens and 3 tens.

Step 4 — Result

Read the complete answer: 85.

xxx47+38x85,sum=85\begin{array}{rrr}\phantom{x}&\phantom{x}&\phantom{x}\\&4&7\\+&3&8\\\hline\\\phantom{x}&8&5\end{array},\quad \text{sum}=85
47 + 38 = 85tens1438ones785+carry 1 ten10 ones+ 5 ones8 tens and 5 ones make 85Put the tens and ones digits together to read the sum.
carry When a column sum reaches 10 or more, write only the ones digit and carry the tens digit to the next column on the left. The carry adds 1 to that column's sum.