More Mental Addition (3-digit numbers)
I show you how to use an easier, helping problem to add a three-digit and a single-digit number, such as 435 + 6. We simply add 35 + 6 first, to get 41. The answer to the original addition problem is then 441. Then we look at two problems, such as 194 + 8, wherethe answer will go over to the next hundred.
In the second video, we're given five different number sentences (equations) with an unknown, and our task is to choose which one(s) match the word problem: "Jeff weighs 33 kg and he is 4 kg lighter than Jeremy. How much does Jeremy weigh?" Solving this, you will practice algebraic thinking. :)
See also
Mental subtraction with three-digit numbers
Math Mammoth Grade 3 curriculum