Phonics -er

Once upon a time a Mammy was baking gingerbread men with her two children. They put all the ingredients into a bowl and used an electric mixer to mix it. The mixer made the sound er,er,er. 
Read these /er/ words to your child and see if they can sound out and write the words.
her
herb
herd
fern
winter
summer
sister
river
butter
bitter
number
Dictation sentences:
1. Put the letter in the mail box.
2. I can see a boat on the river.
3. It is hotter in summer than in winter.