For parents
Adding across ten: help your child explain 8 + 5
Published:
For 8 + 5, a child might count every object from the beginning. Another route is to stop at ten: add two to eight, then add the remaining three. The key is seeing that the total added is still exactly five.
Start with the empty spaces
Draw a ten-frame: two rows of five spaces. Place eight red counters in it, one per space, and five blue counters beside it. Ask how many spaces are empty. If the child cannot see two immediately, let them count the spaces. Check the group of eight and the separate group of five before making a move.
Split five without adding anything extra
Move two blue counters into the empty spaces. Three of the original five remain beside the frame. Say, “We split five into two and three.” Ask the child to point to the two moved counters and the three left over. Nothing has been added to the collection: only its arrangement changed. This gives a meaning to 5 = 2 + 3.
Record the whole calculation
The full frame holds ten counters, with three outside: thirteen altogether. Write 8 + 5 = 8 + 2 + 3 = 10 + 3 = 13. Every equals sign joins expressions with the same value. Ask the child to show the eight, two and three in the model. Cover the written calculation and invite them to explain it in their own words.
Play fill the frame
Make cards showing 6 + 5, 7 + 6, 8 + 4 and 9 + 3. The child chooses one, builds the first addend in red and places the second in blue beside the frame. Before moving anything, they predict how many blue counters will fill the frame and how many will remain. Then test the prediction. Swap roles so the adult follows the child's instructions. No timer or score is needed.
Four questions with answers
1. 6 + 5: four spaces are empty, so split 5 into 4 + 1; 10 + 1 = 11. 2. 7 + 6: use three of the six, leaving three; 10 + 3 = 13. 3. 8 + 4: two go into the frame and two remain, making 12. 4. 9 + 3: one fills the frame and two remain, also making 12. Check both parts of the second addend, not just the answer.
Untangle common mistakes
An answer of 15 for 8 + 5 may mean the child added two and then added all five again. Put the five blue counters aside and physically partition them once more. Avoid writing 8 + 2 = 10 + 3 = 13: ten is not equal to thirteen. With 8 + 1, there is no need to cross ten. This method is a useful choice, not a compulsory step for every addition.
Choose a small next step
Ask, “Why were three left after you moved two?” A clear explanation matters more than speed. Later, a parent can choose a short addition route in Otto Math, available on the App Store, and discuss how one answer was worked out. The frame activity is an offline game described here, not a claim about a feature inside the app.