LOOP Send feedback
Homeschool math, Grade 1, adding within 20

Why does my child write math answers backwards?

8 plus 6 answered 41 in pencil: the right digits, written in reverse order.

For example: 8 + 6 = 41

The right answer is 14. Your child wrote 41 because they had the right number and put the digits down in the wrong order. Lots of kids do this. It's fixable, and you can start tonight. In LOOP we call it "Wrote the digits backwards."

Your child isn't being careless. They probably added fine and got 14. The mix-up came when they wrote it down.

What they wrote8+ 641
The right answer8+ 614
Here is what happened. They added 8 + 6 and got fourteen. "Fourteen" starts with the sound "four," so they wrote 4 first and then 1. The answer came out 41.

Here is the right way. 14 is one ten and four ones. The 1 goes on the left because it's the ten. The 4 goes on the right because it's the ones. So the answer is 14.

Is it this, or something else?

Before you fix anything, look at what they actually wrote.

41Wrote the digits backwards. Right number, wrong order. This is the page you're on.
2Added instead of subtracted, or the other way. They did 8 − 6 when the sign said add.
13 or 15Counted one too many or too few. Off by one, like counting on fingers.
12Got one basic fact wrong. A near miss on the fact itself.

One wrong answer might just be a slip. If the same thing shows up again and again, it isn't. The sheet below will show you whether this is a pattern.

Free printable: 12 problems

Two of these (3 + 3 and 4 + 5) have a one-digit answer, so there is nothing to flip. They are your check. If those two come back right and the other ten have the digits flipped, this is probably the mistake. Check the key below for the exact wrong answers.

It prints on its own page.

Answer key

1. 14, 2. 12, 3. 13, 4. 6, 5. 15, 6. 16, 7. 17, 8. 9, 9. 18, 10. 13, 11. 14, 12. 12.

A child making this mistake will write 41, 21, 31, 51, 61, 71, 81, 31, 41, 21 for problems 1, 2, 3, 5, 6, 7, 9, 10, 11, 12. Every one has the same two digits as the true answer, swapped. Problems 4 and 8 stay correct.

Adding within 20
Name ____________Date ________Add. Use a pencil.
1.8+ 6
2.7+ 5
3.9+ 4
4.3+ 3
5.7+ 8
6.9+ 7
7.8+ 9
8.4+ 5
9.9+ 9
10.6+ 7
11.5+ 9
12.8+ 4
looplearning.org

What to do this week

  1. Day 1: Use dimes and pennies, or base-ten blocks if you have them. Put 8 pennies down, then 6 more. Count them together and push 10 of them into one pile: that's one dime. Now you have 1 dime and 4 pennies. Ask your child to set the dime on the left and the pennies on the right, and then write what they see. If they write 41, ask which pile is the ten. Don't tell them where it goes. Let them point.
  2. Day 2: Same problems, now on paper. Before each answer, have them say out loud: "How many tens? How many ones?" In 8 + 6, that's 1 ten and 4 ones. Tens go on the left. Then they write it.
  3. Day 3: Do the printable again and count how many still came out flipped. If most of the ten are right now, you're good. If they're still flipping them, do Day 1 again.

LOOP does this for every page. Your child does a printed page in pencil. You take a photo. LOOP tells you which mistake showed up on each problem and prints the next page. Your child works on paper the whole time.

Sign up

Tyler Judson, LOOP co-founder. Before LOOP I tutored math, one kid at a time. LOOP is my try at giving every kid that kind of attention without a tutor in the room.

The mistake names are the ones LOOP uses, and the examples were checked by running LOOP's mistake-finder.

Know what your child is missing, on paper.

Sign up