42 quarters = 42× 0.5 = 2 1 (yuan)

The same number of 1 yuan coins is 2 1+6 = 27 yuan more than the same number of 50-cent coins.

The difference between each pair of 1 yuan coins and 50-cent coins is 0.5 yuan.

Count the number of 1 yuan coins.

27 ÷ 0.5 = 54 (piece)

1 yuan coin 54 yuan

50 cents: 54-6 = 48 (yuan)

(that is, 96 coins, 42 more than 1 yuan coins, which is consistent with the meaning of the question)

1 dime 18 * *: 1.8 yuan.

Ming Ming's total donation:

54+48+ 1.8 = 103.8 (yuan)

Comprehensive formula for calculating the number of 1 yuan coins;

(42×0.5+6)÷0.5

=(2 1+6)÷0.5

=27÷0.5

= 54 (pieces)