13
Divisibility rule for 10
Textbook: Part 1, lesson 13, pp. 40–42
GoalKnow and use the divisibility rule for 10.
New words
divisibility rule · bo‘linish alomatilast digit · oxirgi raqammultiple of 10 · 10 ga karraliround number · yaxlit son
Explanation
Divisibility rule for 10: a number that ends in the digit 0 is divisible by 10; a number ending in any other digit is not. To divide by 10 just remove the last zero: 3 450 : 10 = 345. To see whether the value of an expression is divisible by 10, work it out and look at its last digit.
Worked examples
1 200 ends in 0, so 1 200 : 10 = 120. 4 051 ends in 1, so it is not divisible by 10.
25 × 4 = 100 ends in 0, so the product is divisible by 10.
Class activity
“Ends in zero?”: the teacher calls out numbers; children stand up if the number is divisible by 10 and stay seated if not.
Practice
1
From 340, 705, 1 200, 4 051, 90 write those divisible by 10.
340, 1 200, 90
2
Which digit replaces the star so that 47* is divisible by 10?
0
3
2 450 apples were packed 10 to a box. How many boxes were needed?
245
4
Is the sum 1 340 + 2 870 + 590 divisible by 10?
Yes, the sum is 4 800, which ends in 0