Dhyayan Abacus

Step 1: Each column has 1 red bead (worth 5) at the top and 4 blue beads (worth 1 each) below the black bar.

Step 2: Click the red bead to slide it down to the bar (adds 5). Click it again to slide it back up (removes 5).

Step 3: Click a blue bead to slide it up to the bar (adds 1 per bead). Click the top active bead to slide it down (removes 1).

Try This: Set the first column to 5 + 3 by sliding 1 red bead down and 3 blue beads up. The value should show 8!