Question 10
Anna performed two operations. She puts stickers over some of the numbers: the same stickers over the same numbers.
Original diagram:
Editable transcription of the same two operations:
$21-7=$
$2\times$ $=$ 
$+1$
Which number can be found under the sticker?
Original diagram:
Editable transcription of the same two operations:
$21-7=$
$2\times$
$=$ $+1$Which number can be found under the
sticker?