Question

Ricarda earns a $25 allowance each week. How much allowance will she earn after 7 weeks. Explain how to use mental math to solve.

Answer 1

25*7=175 dollars

(1) 5*7=35,write down 5 and advance the 3
(2) 2*7=14, 14+3(from step one)=17 write down 7 and advance the 1
(3) since there is no more digits to do calculations, write down the 1
the answer is 175

(is this the mental math you re talking about?)