Find the missing part. Is it five, 50, or eight?
We’re shown a part–whole model. The number 85 is the whole
number. It’s a two-digit number. It has a tens digit and a ones
digit. This part of the number is the tens
part. The number 85 has eight 10s. We can model eight 10s using eight
10s blocks. Let’s count in 10s. 10, 20, 30, 40, 50, 60, 70, 80. The eight digit in the number 85 is
worth 80. And the five digit in the number 85
is worth five ones. 80 plus five is 85.
The missing part of the number is
five. 85 has eight 10s, which are worth
80, and five ones.