Content Area: Math

 

Index: 4.1B Grade 4 CPI 7

 

Standard: 4.1 - Number and Numerical Operations

 

Strand: B - Numerical Operations

 

Cumulative Progress Indicator: 7 -  The student will select pencil-and-paper, mental math, or a calculator as the appropriate computational method in a given situation depending on the context and numbers and check the reasonableness of results of computations.

 

Grade: 4

 

Sample Activities:

 

·        Students frequently do warm-up drills that enhance their mental math skills. Problems like: 3,000 x 7 = , 200 x 6 = , and 5,000 x 5 + 5 = are put on the board as individual children write the answers without doing any paper-and-pencil computation.

 

·        Students make appropriate choices from among front-end, rounding, and compatible numbers strategies in their estimation work depending on the real-world situation and the numbers involved. Front end strategies involve using the first digits of the largest numbers to get an estimate, which of course is too low, and then adjusting up. Compatible numbers involves finding some numbers which can be combined mentally, so that, for example, 762 + 2,444 + 248 is about (750 + 250) + 2,500, or 3,500.

 

·        Students use money and shopping situations to practice estimation and mental math skills. Is $20.00 enough to buy items priced at $12.97, $4.95, and 3.95? About how much would 4 cans of beans cost if each costs $0.79?

 

·        Students explore estimation involving division as they read The Greatest Guessing Game: A Book about Dividing by Robert Froman. A little girl and her three friends solve a variety of problems, estimating first and discussing what to do with remainders.