I spent $120 shopping for food last week. This week I spent 12% more. Which expression could be used to find how much I spent on food this
week?

 120*1.12

The multiplier 1.12 represents the idea of increasing by 12%

This is because 100% + 12% = 1 + 0.12 = 1.12

For example, if you spend $100 this week and increase that by 12%, then you'll spend 100*1.12 = 112 dollars next week. Note how 12% of 100 is 12, which is the amount the budget goes up.

where's the diagrams?