What math facts should a 1st grader know?

Add and subtract within 20, with the facts within 10 down well.

By the end of 1st grade

Add and subtract within 20, and be fluent with addition and subtraction within 10. (1.OA.C.6)

These come from the Common Core State Standards for Mathematics, which most US states use or have adapted. Your child's school may word them differently.

What that looks like

Facts within 10, answered quickly: 6 + 3 = 9, 10 − 4 = 6.
Making a 10 for bigger sums: 8 + 6 = 8 + 2 + 4 = 10 + 4 = 14.
Using addition to subtract: 8 + 4 = 12, so 12 − 8 = 4.

How to practice at home

A few minutes a day works better than a long session once a week.

1-minute addition test (facts within 10)
1-minute subtraction test (facts within 10)
Mental math tricks (make a 10)

Take the 1-minute addition test

Common questions

How long should my child practice math facts each day?

A few minutes a day is enough for most kids. Short, regular practice sticks better than a long session once a week.

My child still counts on their fingers. Is that a problem?

Counting is a normal step on the way to knowing facts from memory. Strategies like making a 10 bridge the gap, and a 1-minute test shows which facts are still slow.