Skill: Add a 2-digit number and a 1-digit number

Explanation and Free Practice Resources

This skill involves interpreting a two-digit number as tens and ones and combining it with a one-digit addend, including cases in which the ones require composing a new ten (for example, 47 + 6 = 53). Reasoning may be represented with place-value drawings, equations, or an open number line, emphasizing that the added one-digit quantity changes ones and, when necessary, the tens; it does not include adding two multi-digit numbers or extending to more general algorithms.

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Detailed Explanation: Add a 2-digit number and a 1-digit number

To add a 2-digit number and a 1-digit number, start with the ones. If the ones make 10 or more, regroup 10 ones as 1 new ten.

Example: Find $(47+6)$ .

Break apart $(47)$ :

47=4\text{ tens}+7\text{ ones}

Add the 6 ones:

7+6=13

That is $1$ ten and $3$ ones.

Combine the tens:
The original $4$ tens plus the new $1$ ten makes $5$ tens.
Put the tens and ones together:

5\text{ tens}+3\text{ ones}=53

So,

\boxed{47+6=53}

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Addition - Whole Number 2 digit + 1 digit - Column, With Carry

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