Question

Nathan deposited 7/9 of his allowance into his savings account. He spent the remaining ammount, or $2.50. How much did Nathan deposit into his savings account?

Answer 1

If he deposited 7/9 then he spent 2/9.
See 7/9 + 2/9 = 9/9

then if $2.50 is 2/9 we divide $2.50 by 2
 which makes $1.25 equal to 1/9

1/9 × 7 = 7/9 (amount deposited)

$1.25 × 7 = $8.75