Rounding decimals –
Underline the place value, look to the right. If # to right is 5 or more, round up. 4 or less, # stays
Example: 1.8356 thousandths
1.) 54.936 hundredths 2.) 132.09234 ones 3.) 2.362 Tenths
Estimating decimals –
Find compatible numbers close to the given number, then perform given operation
Example: 91.394 + 11.0293 à 90 + 10 = 100
4.) 52.924 x 4.23 5.) 26.43 ÷ 4.834 6.) 76.0394 – 24.42
Adding and Subtracting decimals –
Line up decimals, add zeros if necessary, add decimal in sum or difference, perform operation
Example: 2.543 + 13.93
7.) 34.0945 + 123.4823 8.) 2.34 + 12.032 9.) 0.0345 + 3.842
10.) 43.104 – 12. 284 11.) 12.34 – 6.21 12.) 16.5 – 0.0452
Multiplying decimals –
Stack multiples (longer on top), slide multiples to the right (drop any zeros at the end of decimals), solve by multiplying, count numbers right of the decimal, add decimal into product.
Example: 23.930 x 1.9
13.) 4.384 x 3 14.) 14.31 x 4.2 15.) 435.2 x 6.1
16.) 5.04 x 0.02 17.) 97.31 x 4.1 18.) 6.900 x 4
