# 5th Grade - Work With Very Large And Small Numbers

 Grade Level: 5th Skill: Numbers - Small, Large and Prime Topic: Work with Very Large and Small Numbers Goal: Estimate, round, and manipulate very large (e.g., millions) and very small (e.g., thousandths) numbers. Skill Description: Students must know place values to the right and the left of the decimal place. Students must also be able to round a number in a specific way by first identifying which place value was directed and then knowing the rules of rounding up/down.

## Building Blocks/Prerequisites

### Sample Problems

 (1) What number is in the hundred-thousands place? 2,763,532.949 (7) (2) What number is in the hundredths place? 2,763,532.949 (5) (3) What is the relationship between hundreds and hundredths? (hundreds are more than 0, hundredths are less than 0) (4) Round this number to the nearest ten-thousands 5,875,653.29 (7) (5) Round this number to the nearest tenth 5,875,653.29 (2)

### Learning Tips

 (1) If your child is confused by place value order, try color coding each place. Ones are red, tens are orange, hundreds are yellow, etc. (2) When your child is beginning to include decimal place value in their studies, it helps if you accentuate the “d” on the end of the hundred and the “th” on the end of the hundredths. They find it silly to say hundredddddddds at first, but they always remember it better. (3) The stock market is full of large numbers. Grab a page from the newspaper or from the Internet and have your student round those numbers to the nearest…it’s “real world” practice. (4) Rounding decimals is easy when you use spare change. Kinesthetic learners love it, but everyone understands that they don’t want to count out all those coins. (5) When students ask me “why do I have to round if I just have to find the exact answer anyway?” I always show them how rounding helps on a multiple choice test (and they have to take plenty high stakes testing during the year). If I round my numbers and use mental math before I begin solving the problem, I can eliminate one, sometimes two or three, answers before I even begin my “work.”

### Online Resources

 (1) (2) (3) (4) (5)

### Extra Help Problems

 (1) Round to the nearest hundredth .4923 (.49) (2) Round to the nearest hundredth .6379 (.64) (3) Round to the nearest hundred thousand 9,371,826.42 (9,370,000.00) (4) Round to the nearest million 2,543,982.739 (3,000,000.00) (5) Round to the nearest ten thousand 8,265,629.302 (8,270,000.000) (6) Estimate the sum 8,563 +64,872 (9000 + 65,000 = 74,000) (7) Estimate the sum 9,369,947 + 6,486,957 (9,000,000 + 6,000,000 = 15,000,000) (8) Estimate the sum .838 +.942 (.8 + .9 = 1.7) (9) Estimate the sum .428 + .729 (.4 + .7 = 1.1) (10) Estimate the sum 8,439,197 + 4, 291,836 (8,000,000 + 4,000,000 = 12,000,000) (11) Estimate the difference 17,943 – 3,545 (18,000 – 4,000 = 14,000) (12) Estimate the difference 5,478,327 – 1,837,256 (5,000,000 – 2,000,000 = 3,000,000) (13) Estimate the difference 7.84 – 2.63 (8-3 = 5) (14) Estimate the difference 78.32 – 49.29 (78-49 = 29) (15) Estimate the difference 5,943 – 2,965 (6,000 – 3,000 = 3,000) (16) Estimate the product 19.6 X 5.43 (20x5 = 100) (17) Estimate the product 24.76 X 4.49 (25x4=100) (18) Estimate the product 5,028,917 X 1,473,039 (5,000,000 x 1,000,000 = 5,000,000) (19) Estimate the product 6,938 X 7,362 (7,000 x 7,000=49,000) (20) Estimate the product 479,246 x 241,937 (500,000 x 200,000 = 1,000,000) (21) Estimate the quotient 35.47 / 5.32 (35/5=7) (22) Estimate the quotient 80.51 / 8.88 (81/9=9) (23) Estimate the quotient 41.77 / 5.9 (42/6=7) (24) Estimate the quotient 76.35 / 2.09 (76/2=38) (25) Estimate the quotient 50.46 / 4.87 (50/5=10)