Question: A storekeeper found 12 hats left at the store this week. His records shows that 13 hats were sold last week. Choose the number sentence to calculate h, the number of hats that were there in the store at the begining of last week.
A ) 13 - 12 = h B ) 12 + 13 = h C ) 13h = 12 D ) 12h = 13
Steps to derive
1 Let h be the number of hats last week.
2h = number of hats the store has this week + the number of hats the store sold last week.
3h = 12 + 13.
[Substitute the values.]
4 So, the number sentence used to calculate the number of hats, store have at the begining is, 12 + 13 = h.
