Number blocks are used to represent numbers visually, making it easier to understand place value. For the number 342, we use 3 hundreds blocks, 4 tens blocks, and 2 ones blocks.For 123, we use 1 hundred block, 2 tens blocks, and 3 ones blocks. The number 478 is shown with 4 hundreds blocks, 7 tens blocks, and 8 ones blocks. For 320, we place 3 hundreds blocks, 2 tens blocks, and no ones block. Lastly, 194 is represented by 1 hundred block, 9 tens blocks, and 4 ones blocks.