standard_description: Add within 100, including adding a two-digit number and a one-digit number, and adding a two-digit number and a multiple of 10, using concrete models or drawings and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction; relate the strategy to a written method and explain the reasoning used. Understand that in adding two-digit numbers, one adds tens and tens, ones and ones; and sometimes it is necessary to compose a ten.
problem_activity: Problem 1
Round to the place mentioned below. Show or explain your thinking.
a.   Round 4,862 to the nearest thousand.
4,862 ≈ ___________
b.   Round 308,724 to the nearest hundred thousand.
308,724 ≈ __________
Problem 2
There are 97,385 people who live in Boulder, Colorado. Cathy thinks that rounds to about 100,000 people. Alonzo thinks it rounds to 90,000 people. Who rounded correctly, Cathy or Alonzo? Show or explain your thinking.


aligns: no