Teacher's Edition Grade 4 Topic 4 - Envision Math, California Author:Scott Foresman Multiplying by 1-Digit Numbers. Multiples of 10 and 100. Mental math to multiply. rounding to estimate. expanded algorithm. 2-Digit by 1-Digit numbers. 3-Digit by 1-Digit numbers. Multiplying greater numbers by 1-Digit numbers. Problem Solving: Reasonableness.