KA-0055Place value and digit positions
3 points, difficulty 1 of 3Level 3–4about 30sIn the number 4073, what is the value of the digit 7?
Hints
Take them one at a time. The first gives nothing away.
1A nudge
Name each position from the right.
2The strategy
Reading from the right, the positions are ones, tens, hundreds, thousands. Find which one the 7 sits in, then say what one unit of that position is worth.
3The full solution
From the right: 3 is in the ones, 7 is in the tens, 0 is in the hundreds, 4 is in the thousands. Seven tens is 70.
Solution— no shortcut on this one
Label the positions from the right: ones, tens, hundreds, thousands. The 3 is in the ones, so the 7 is in the tens. Seven tens is 70. The transferable idea: a digit's value is the digit multiplied by what its position is worth, and positions are counted from the right.
Why this is on the test: Everything about digits rests on this, and counting positions from the left instead of the right is the error that survives longest.