.number0 {background-image: url('../images_numbers/1_30x24.gif');}
.number1 {background-image: url('../images_numbers/2_30x21.gif');}
.number2 {background-image: url('../images_numbers/3_30x22.gif');}
.number3 {background-image: url('../images_numbers/4_30x24.gif');}
.number4 {background-image: url('../images_numbers/5_30x24.gif');}
.number5 {background-image: url('../images_numbers/6_30x26.gif');}
.number6 {background-image: url('../images_numbers/7_30x22.gif');}
.number7 {background-image: url('../images_numbers/8_30x22.gif');}
.number8 {background-image: url('../images_numbers/9_30x22.gif');}
.eraseButton {background-image: url('../images/erase.gif');}